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% - Retains the original shared statement numbering 1--69.
% - Adds independently numbered Interface propositions.
% - Makes complete control/storage accounting explicit.
% - Proves the channel causal-cut and process-law statements locally.
% - Separates record, residual-instrument, and mechanism identification.
% - Adds an explicit classical-register memory witness.
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% https://www.frontiersin.org/journals/physics/articles/
% 10.3389/fphy.2026.1954943/abstract
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\hypersetup{
  pdftitle={Observation Boundaries for Destructive Quantum Readout and External Geometry},
  pdfsubject={En03-A: typed interfaces, causal cuts, records, residual instruments, and certified geometric events},
  pdfkeywords={destructive measurement, quantum channels, noninterference,
    deferred measurement, instruments, external geometry, causal cuts}
}

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\Crefname{openproblem}{Open problem}{Open problems}
\crefname{interfaceprop}{Interface proposition}{Interface propositions}
\Crefname{interfaceprop}{Interface proposition}{Interface propositions}

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\newcommand{\Enter}{\operatorname{Enter}}
\newcommand{\CPTP}{\mathrm{CPTP}}
\newcommand{\Jsched}{J_{\mathrm{sched}}}
\newcommand{\Lor}{\mathrm{SO}^{+}(2,1)}

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\title{Observation Boundaries for Destructive Quantum Readout\\
and External Geometry}
\author{}
\date{\small Manuscript En03-A}

\begin{document}

\maketitle

\begin{abstract}
We formulate a finite, linearly typed interface for destructive
computational-basis measurement, external classical geometry, and
declared matter--geometry coupling. The observation boundary includes
not only coupling observables but also control, guards, capacity tests,
locations, and retained storage. Under explicit noninterference
hypotheses, arbitrary spectator extensions with the same accessible
reduction preserve geometric traces. Immediate destructive readout and
a restricted coherent-then-readout implementation agree on their common
record--matter output.

For a channel \(T\), coarse effects \(E_w\), and aggregated fine
effects \(\Pi_w\), record compatibility for every input is equivalent
to \(T^*(E_w)=\Pi_w\). Its exact unassisted worst-case total-variation
error is an event operator norm. Residual compatibility requires a
separate instrument certificate. Complete-record equality does not
identify a hidden mechanism; a persistent classical register can
produce carrier-only history dependence.

Prescribed finite channel networks admit a causal-cut factorization
through their scheduled ancestors, including in the presence of an
untouched reference. This channel statement is not transferred to
nonlinear geometric coupling. Conditional stability, integrated
residual, and independent-run sampling certificates are stated with
their additional hypotheses.

An external conical witness, a static gauge flip, and one complete
four-face adjacency exchange illustrate the interface. The exchange
has explicit charts, edge laws, event germs, an exact guard, a compact
collar, location transport, and a finite reversible event
implementation. The ambient spacetime is fixed. No gravitational
field equation, continuum limit, or quantum-memory-resource theorem
is asserted.
\end{abstract}

\section{Introduction}

A geometric extension of a quantum programming language must specify
what geometry can observe. This requirement is independent of the
choice of gravitational dynamics or a continuum limit. Linear
ownership of quantum names does not determine a mass; a measurement
record is not a coarse-graining map; and a circuit dependency region
is not automatically a physical light cone.

We use a finite circuit interface with destructive readout
\begin{equation}
 \Enter:\Qtype^{\otimes n}\longrightarrow\Bit^{\otimes n}.
 \label{eq:enter-type}
\end{equation}
Its semantics is the Born destructive computational-basis measurement
used by Cheung's Enter calculus~\cite{Cheung2026Enter,CheungI}.
Measured quantum names are consumed, and their tensor factors are not
returned. We do not reprove a language-wide type-safety theorem or
derive the Born rule. Our mixed-state channel presentation is a
finite-dimensional semantic interface for that measurement operation.

Four additional structures are declared:
\begin{enumerate}
\item an external classical geometric configuration;
\item a location map for active matter names;
\item coupling algebras specifying accessible matter observables;
\item a complete control and resource interface specifying update
      selection, applicability, support, and retained storage.
\end{enumerate}
Geometry is primitive metadata, not a quantity inferred from name
cardinality, measurement count, or workspace size.

Two distinctions organize the paper:
\begin{equation}
 \boxed{\begin{gathered}
 \text{Record compatibility is a pullback;}\\
 \text{residual compatibility is a separate instrument certificate.}
 \end{gathered}}
 \label{eq:record-boundary-summary}
\end{equation}
\begin{equation}
 \boxed{\begin{gathered}
 \text{Scheduled ancestors bound influence;}\\
 \text{a classical register can retain carrier-only history dependence.}
 \end{gathered}}
 \label{eq:schedule-memory-summary}
\end{equation}

\subsection{Results and dependencies}

The main results are:
\begin{enumerate}
\item exact finite-step support containment and causal-cut
      factorization for prescribed channel dynamics;
\item retiming invariance for a fixed labelled gate partial order;
\item spectator-extension invariance under complete control and
      resource blindness;
\item restricted destructive deferred-readout equivalence;
\item an effect-pullback criterion and exact unassisted record error;
\item a residual-instrument obstruction and accessible-algebra
      comparison criteria;
\item a complete fixed-spacetime certificate for one four-face
      adjacency exchange.
\end{enumerate}
Supplementary interface propositions give complete-process record
laws, a classical-register memory witness, and conditional
approximation and sampling bounds.

Finite-dimensional channel conventions follow
Watrous~\cite{Watrous2018}. The circuit precedent for deferred
measurement is Gurevich and Blass~\cite{GurevichBlass2022}.
The geometric setting uses conical point-particle spacetimes and
polygonal developments~\cite{DeserJackiwHooft1984,tHooft1992,
tHooft1993,Kadar2005}.

Cheung's companion records motivate comparisons with observation,
process, and schedule interfaces~\cite{CheungVIIE,CheungVIIJ,
CheungPsy02A,CheungPsy02B}. They are not premises transferring a
model identity or a gravitational solution. Every mathematical
statement used here is formulated and proved locally. The source
ledger in \cref{app:sources} distinguishes full supplied passages from
statement summaries; no inspection of an entire manuscript corpus
is claimed.

\subsection{Scope}

The configuration space may contain arbitrary real lengths and affine
isometries. These remain external labels unless a finite code and
decoder are supplied. The executable examples cover only declared
finite families.

A geometric coupling may be nonlinear in the matter state.
Consequently the complete coupled evolution is not generally a
quantum channel. Channel locality, no-signalling, distance contraction,
and retiming are asserted only for the prescribed channel objects
named in their statements.

The four-face construction changes the cellulation of a prescribed
slicing of an already fixed spacetime. It is not a new gravitational
solution, a particle-supported transition, or an implementation of the
full polygon model. No field equation, curvature-convergence theorem,
Newtonian limit, or equivalence of matter clocks and propagation cones
is proved.

\section{Typed interfaces and semantic configurations}

\subsection{Finite-dimensional conventions}

All matter, code, and record spaces used in channel statements are
finite-dimensional. Write \(L(\cH)\) for the operator space and
\(D(\cH)\) for its density operators. A channel is a completely
positive, trace-preserving linear map. Its adjoint satisfies
\begin{equation}
 \Tr(A\Phi(\rho))=\Tr(\Phi^*(A)\rho).
 \label{eq:adjoint}
\end{equation}
Channel adjoints are unital and completely
positive~\cite{Watrous2018}.

A classical register has a distinguished basis. An admissible joint
state is block diagonal in that register, not merely diagonal after
taking its marginal. Declared classical operations preserve this
joint block-diagonal state space. Their individual Kraus operators
need not be diagonal; classical permutations are allowed.

For a unital \(^{*}\)-subalgebra \(\cA\), define
\begin{equation}
 \omega_\rho|_{\cA}:A\longmapsto\Tr(\rho A).
 \label{eq:state-functional}
\end{equation}
Equality of these functionals means equality on the named observable
interface.

Our distance conventions are
\begin{equation}
 \tv(p,q)=\frac12\sum_w\abs{p(w)-q(w)},
 \qquad
 \td(\rho,\sigma)=\frac12\norm{\rho-\sigma}_1.
 \label{eq:distance-conventions}
\end{equation}
The trace norm itself has no factor \(1/2\).
Outcome sets and complete history alphabets are finite unless
explicitly stated otherwise.

\subsection{A minimal linear circuit interface}

Wire types are generated by
\[
 A::=I\mid\Qtype\mid\Bit\mid A\otimes A.
\]
A judgement \(f:A\to B\) consumes the entire input interface and returns
the specified output interface. Formation includes identities,
permutations, sequential composition, and tensor composition:
\[
 \frac{f:A\to B\qquad g:B\to C}{g\circ f:A\to C},
 \qquad
 \frac{f:A\to B\qquad g:C\to D}
      {f\otimes g:A\otimes C\to B\otimes D}.
\]
The circuit constants used here are unitary gates, preparation
of \(\ket0\), and destructive computational-basis measurement.
Finite reversible code operations use NOT, CNOT, and Toffoli.
Classical zero preparation and classical reversible gates act on
\(\Bit\) interfaces; their basis-permutation unitary lifts act on
\(\Qtype\) interfaces. No conversion between these types is implicit.

Linearity concerns ownership. Successive gates may consume and return
the same physical factor. No rule duplicates a live quantum wire.

% 1
\begin{remark}[Relation to a larger calculus]
\label{rem:calculus}
The interface is specified independently of the complete language.
An embedding into the full calculus of~\cite{Cheung2026Enter}
must match its constants, typing, and circuit-adequacy interface.
No theorem below relies on the Layer II measurement-uniqueness
argument or asserts gate-library realization of every semantic
channel.
\end{remark}

\subsection{Three measurement interfaces}

Let \(S\) have computational basis \(\{\ket z:z\in Z\}\), and let \(B\)
be its accessible complement. Put
\[
 M_z=\bra z_S\otimes I_B:\cH_{SB}\longrightarrow\cH_B.
\]

% 2
\begin{definition}[Destructive \(\Enter\)]
\label{def:enter}
The destructive measurement channel is
\begin{equation}
 \cM_S(\rho)
 =\sum_z\ket z\bra z_R\otimes M_z\rho M_z^\dagger,
 \qquad
 \cM_S:L(\cH_{SB})\longrightarrow L(\cH_{RB}).
 \label{eq:destructive}
\end{equation}
The record \(R\) is classical. The factor \(S\) is absent.
The circuit operation \(\Enter_S\) is interpreted by \(\cM_S\).
\end{definition}

This is destructive Born readout, not a returned measured quantum
register~\cite{Cheung2026Enter,CheungI}.

% 3
\begin{definition}[Coherent recording]
\label{def:recording}
A fresh quantum carrier \(A\), with basis indexed by \(Z\), is
introduced by the isometry
\begin{equation}
 V:\cH_{SB}\longrightarrow\cH_{SAB},
 \qquad
 V(\ket z_S\otimes\ket b_B)
 =\ket z_S\otimes\ket z_A\otimes\ket b_B.
 \label{eq:copy-isometry}
\end{equation}
Its channel is \(\Copy_S(\rho)=V\rho V^\dagger\).
For qubits it is zero preparation followed by CNOT.
\end{definition}

% 4
\begin{definition}[Represented nondestructive instrument]
\label{def:nondestructive}
For \(P_z=\ket z\bra z_S\otimes I_B\), set
\begin{equation}
 \cI_S^{\mathrm{nd}}(\rho)
 =\sum_z\ket z\bra z_R\otimes P_z\rho P_z.
 \label{eq:nondestructive}
\end{equation}
Its residual interface is \(S\otimes B\). It is not the destructive
primitive.
\end{definition}

\begin{center}
\begin{tabular}{@{}llll@{}}
\toprule
Operation & \(S\) returned & Record & Role\\
\midrule
\(\Enter_S\) & No & Classical & Destructive primitive\\
\(\Copy_S\) & Yes & Quantum carrier & Isometric recording\\
\(\cI_S^{\mathrm{nd}}\) & Yes & Classical & Residual instrument\\
\bottomrule
\end{tabular}
\end{center}

Coherent recording does not clone arbitrary states:
\[
 V\ket+=\frac{\ket{00}+\ket{11}}{\sqrt2}
 \ne
 \ket+\ket+
 =\frac{\ket{00}+\ket{01}+\ket{10}+\ket{11}}2.
\]
Deferred \(\Enter\) means recording, continuation on the declared
complement, destructive carrier readout, and comparison after
restriction away from retained \(S\).

\subsection{External geometry and transition strata}

% 5
\begin{definition}[External geometric interface]
\label{def:external}
A geometric interface specifies:
\begin{enumerate}
\item a set \(\cQ\) of classical configurations;
\item an admissible subset
\begin{equation}
 \cQ_{\mathrm{adm}}=\cQ_{\mathrm{reg}}\cup\cQ_{\mathrm{tr}};
 \label{eq:admissible-strata}
\end{equation}
\item a finite label set \(\Cell(q)\) for each configuration;
\item support, admissibility, and resource certificates for updates;
\item optionally, a supplied gauge equivalence \(\sim_g\).
\end{enumerate}
Regular configurations satisfy the model's stated nondegeneracy
conditions. Transition configurations require a model-specific
event certificate and may retain one-sided germ labels whose common
geometric realization is degenerate.

Admissibility is semantic. A finite representation and a decision
procedure are additional structures.
\end{definition}

In \cref{sec:geometry}, every bounded regular edge has positive
length. Fixed unbounded exterior rays, when used, are described as
rays rather than finite length reports. At the event, a vanishing
central edge and coincident endpoint labels are germ metadata, not
a regular embedded one-cell.

% 6
\begin{definition}[Geometry--matter configuration]
\label{def:configuration}
A configuration is
\begin{equation}
 C=(q;\Gamma;\rho;\loc),
 \qquad
 \loc:\Gamma\longrightarrow\Cell(q),
 \label{eq:configuration}
\end{equation}
where \(q\in\cQ_{\mathrm{adm}}\), \(\Gamma\) is a finite labelled
interface, and \(\rho\in D(\cH_\Gamma)\). Classical names satisfy
joint block diagonality. The geometric projection is \(\pi_g(C)=q\).

Control and resource labels are either included in \(q\) or carried
as separately declared classical data. Compared executions have
equal initial declared control and resource data.

Permitted transition-germ locations, their realizations, and their
transport belong to the event certificate.
\end{definition}

Interfaces may change under commands. Destructive measurement replaces
measured quantum names by fresh record names. An identity extension
always refers to the current unacted-on interface.

\subsection{Three rule kinds}

% 7
\begin{definition}[Certified interface rules]
\label{def:rules}
A finite run uses:
\begin{enumerate}
\item A \emph{geometric rule}, or \((G)\)-rule, which replaces
supported geometric labels by a specified function of those labels
and declared resources. It does not inspect matter state or
matter-name cardinality. Its complete output is admissible and
includes location transport.

A transition rule specifies incoming and outgoing germs, their
common event realization, and both one-sided continuations.

\item A \emph{matter rule}, which applies a declared channel
\begin{equation}
 \Psi_q:L(\cH_{\Gamma_0})\longrightarrow L(\cH_{\Gamma'_0})
 \label{eq:matter-rule}
\end{equation}
on a named local interface, tensored with the identity on the
remaining names. It may depend on \(q\), but does not change \(q\).
Allocation and output locations are part of its certificate.

\item A \emph{coupling rule}, which declares a unital observable
algebra \(\cA_v\) and updates geometry by
\begin{equation}
 q'=F_v(q,\omega_\rho|_{\cA_v}).
 \label{eq:coupling}
\end{equation}
It returns a complete admissible configuration and a location
transport map. It leaves the matter density operator unchanged.
\end{enumerate}
\end{definition}

Changing one particle scalar while freezing incompatible chart data
need not preserve constraints. A coupling therefore returns a complete
certified update, not merely a new scalar.

% 8
\begin{remark}[Nonlinear backreaction]
\label{rem:nonlinear}
The map in \cref{eq:coupling} need not be affine in \(\rho\).
The complete coupled evolution is not generally \(\CPTP\).
The noninterference proofs compare equal coupling inputs; they do
not establish no-signalling for arbitrary nonlinear backreaction.
\end{remark}

\subsection{Complete control and resource accounting}

The controller selects commands, guards, support, and capacity checks.
Every state-dependent register, queue, timing signal, applicability
predicate, and readable transport history is part of that interface.

% 9
\begin{assumption}[Spectator-blind control]
\label{ass:sched}
For the compared executions, inaccessible spectators do not change:
\begin{enumerate}
\item the selected command or its declared matter channel;
\item guard, applicability, or capacity-check results;
\item the support, block membership, or transport of original names;
\item successor control and declared resource data.
\end{enumerate}
The controller is a specified function of the complete declared inputs.
Equal such inputs select the same update and certificate. No
undeclared spectator-dependent input is available to it.

The location transports are defined on all permitted spectator
locations, and spectator storage and transport history have separately
reserved resources sufficient for the compared run.

Randomized controllers are aligned using a common input-independent
seed, or a specified coupled law satisfying the same equality property.
\end{assumption}

Separate reservation is not a claim of unlimited physical memory.
It is a hypothesis about which finite resource budget controls the
geometric update. A global occupancy test may violate the hypothesis.

% 10
\begin{definition}[Gauge and admissible geometric observables]
\label{def:gauge}
Gauge equivalence is a supplied equivalence relation on geometric
descriptions. In the examples it includes chart changes and
retriangulations representing the same metric and marked slice.
An admissible geometric observable is constant on its equivalence
classes.

A fixed spacetime does not identify all marked-slice observables at
different times. Circuit retiming is not presumed to be a gauge
symmetry of nonlinear coupled evolution.
\end{definition}

\section{Kinematics and causal cuts on a prescribed schedule}
\label{sec:schedules}

Throughout this section the channel list, metric, and schedule are
prescribed. State-dependent geometric selection is not hidden inside
a channel list.

\subsection{Scheduled blocks}

% 11
\begin{definition}[Scheduled matter dynamics]
\label{def:schedule}
Let \((X,d)\) be a finite metric space with site spaces \(\cH_x\), and
write
\[
 \cH_X=\bigotimes_{x\in X}\cH_x,
 \qquad
 \cA(Y)=L\left(\bigotimes_{x\in Y}\cH_x\right)
          \otimes I_{X\setminus Y}.
\]
For \(a,\tau>0\), let \(\mathcal B_t\) be a partition of \(X\) at
tick \(t=1,\ldots,T\), with
\[
 \diam_d B\le R_{\mathrm{upd}}a.
\]
The dynamics is
\begin{equation}
 \Phi_t=\bigotimes_{B\in\mathcal B_t}\Phi_{t,B},
 \qquad
 c_{\mathrm{sched}}=\frac{R_{\mathrm{upd}}a}{\tau},
 \label{eq:scheduled-dynamics}
\end{equation}
where each block map is a channel on its reserved site interface.
\end{definition}

Readout may write a reserved local record register. A fixed ambient
description may contain an inactive placeholder after destruction;
that placeholder is not an accessible surviving measured wire.

% 12
\begin{definition}[Schedule past]
\label{def:schedule-past}
For \(Y\subseteq X\) and \(0\le s\le t\le T\), set
\begin{equation}
 \begin{aligned}
 N_{t,t}(Y)&=Y,\\
 N_{s,t}(Y)&=
 \bigcup\{B\in\mathcal B_{s+1}:
                B\cap N_{s+1,t}(Y)\ne\varnothing\},
 \qquad s<t,
 \end{aligned}
 \label{eq:cone}
\end{equation}
and
\begin{equation}
 \Jsched^-(Y,t)
 =\{(x,s):0\le s\le t,\ x\in N_{s,t}(Y)\}.
 \label{eq:schedule-past}
\end{equation}
\end{definition}

% 13
\begin{lemma}[One-layer support]
\label{lem:one-layer}
If \(\Phi=\bigotimes_{B\in\mathcal B}\Phi_B\) and \(A\in\cA(Y)\), then
\begin{equation}
 \supp\Phi^*(A)
 \subseteq\bigcup\{B\in\mathcal B:B\cap Y\ne\varnothing\}.
 \label{eq:one-layer-support}
\end{equation}
\end{lemma}

\begin{proof}
Let \(Y'\) be the displayed union. Its complement is a union of
blocks. Unitality on those blocks gives
\[
 \Phi^*(A_{Y'}\otimes I_{X\setminus Y'})
 =\Phi_{Y'}^*(A_{Y'})\otimes I_{X\setminus Y'}.
\]
\end{proof}

% 14
\begin{theorem}[Exact schedule locality]
\label{thm:locality}
For \(A\in\cA(Y)\) and \(0\le s\le t\le T\):
\begin{enumerate}[label=(\roman*)]
\item
\begin{equation}
 \supp((\Phi_{s+1}^*\circ\cdots\circ\Phi_t^*)(A))
 \subseteq N_{s,t}(Y);
 \label{eq:locality-support}
\end{equation}
\item
\begin{equation}
 N_{s,t}(Y)
 \subseteq\{x:d(x,Y)\le(t-s)R_{\mathrm{upd}}a\};
 \label{eq:locality-range}
\end{equation}
\item the output reduction on \(Y\) depends on the state at tick \(s\)
only through its reduction to \(N_{s,t}(Y)\).
\end{enumerate}
\end{theorem}

\begin{proof}
Reverse-tick induction using \cref{lem:one-layer} proves (i).
For (ii), if \(x\) enters through a block meeting the next region at
\(y\), then
\[
 d(x,Y)\le d(x,y)+d(y,Y)
 \le R_{\mathrm{upd}}a+(t-s-1)R_{\mathrm{upd}}a.
\]
For (iii), every output observable pulls back to the named input
region. Equality of its expectations for all output observables
is equality of the output density operators.
\end{proof}

% 15
\begin{corollary}[Readout laws and prescribed interventions]
\label{cor:local-records}
A prescribed readout at \((Y,t)\) depends only on the initial reduction
to \(N_{0,t}(Y)\). Replacing a block channel outside its backwards
dependency region does not change the readout law, provided the
declared schedule and interfaces are retained.
\end{corollary}

\begin{proof}
Readout effects are output observables. On an excluded block the
pulled-back observable is the identity, which every replacement
channel adjoint preserves.
\end{proof}

% 16
\begin{remark}[Containment and complete laws]
\label{rem:schedule-containment}
Scheduled ancestors are an exact upper bound, not necessarily the
minimal influence region of a particular channel. Joint records use
the backwards region of their full instrument network. Selective
normalized updates are not trace-preserving channels; the statements
concern unconditional channels that retain their records.
\end{remark}

\subsection{The channel causal-cut criterion}

The schedule statement has a factorization form. This is the channel
interface compared with Cheung's schedule and no-signalling source
records~\cite{CheungVIIJ}; the proof here does not import a physical cone.

\begin{interfaceprop}[No-signalling, factorization, and adjoint inclusion]
\label{ip:nosignal}
For a channel
\(\Theta:L(\cH_A\otimes\cH_C)\to L(\cH_B)\), the following are
equivalent:
\begin{enumerate}[label=(\roman*)]
\item \(\Theta(\rho)=\Theta(\sigma)\) whenever
      \(\Tr_A\rho=\Tr_A\sigma\);
\item there is a channel \(\theta:L(\cH_C)\to L(\cH_B)\) with
\begin{equation}
 \Theta=\theta\circ\Tr_A;
 \label{eq:cut-factorization}
\end{equation}
\item
\begin{equation}
 \Theta^*(L(\cH_B))\subseteq I_A\otimes L(\cH_C).
 \label{eq:cut-adjoint}
\end{equation}
\end{enumerate}
These conditions imply invariance of the joint \(B\)--reference
output under every local trace-preserving intervention on \(A\),
with the reference untouched.
\end{interfaceprop}

\begin{proof}
Assume (i), fix \(\tau_A\in D(\cH_A)\), and define
\(\theta(X)=\Theta(\tau_A\otimes X)\). This is a channel.
Property (i) proves (ii) on states, hence on all operators by
linear spanning.

The adjoint of \(\Tr_A\) is \(Y\mapsto I_A\otimes Y\), so (ii)
implies (iii). Conversely, (iii) says that every output expectation
is determined by the \(C\)-reduction, proving (i).

For an untouched reference \(E\), the factorization extends as
\[
 \Theta\otimes\id_E
 =(\theta\otimes\id_E)\circ\Tr_A.
\]
If \(\mathcal J_A\) is a channel, then
\(\Tr_A[(\mathcal J_A\otimes\id_{CE})(\rho_{ACE})]
=\Tr_A\rho_{ACE}\), as follows by testing against observables on
\(C\otimes E\) and using \(\mathcal J_A^*(I_A)=I_A\).
\end{proof}

\begin{interfaceprop}[Complete finite-network ancestor cut]
\label{ip:networkcut}
Consider a finite acyclic network of fixed channels, with every
quantum, classical-control, record, and resource wire included.
For an output interface \(B\), let \(\mathrm{Sch}^-(B)\) be the input
wires reached by reverse traversal: whenever an output wire of a
channel box is reached, include every input wire of that box.

If \(\mathrm{Comp}\) is the network channel and \(X\) its input
interface, then
\begin{equation}
 \mathrm{Comp}^*(L(\cH_B))
 \subseteq
 L(\cH_{\mathrm{Sch}^-(B)})
       \otimes I_{X\setminus\mathrm{Sch}^-(B)}.
 \label{eq:network-cut}
\end{equation}
The reduced output channel on \(B\) factors through the scheduled
input ancestors. Inputs disjoint from that cut have zero signalling
to \(B\), including with an untouched reference.
\end{interfaceprop}

\begin{proof}
Choose a reverse topological ordering. Pull an observable on \(B\)
back through each box. If it is identity on all outputs of a box,
unitality leaves identity on all inputs. Otherwise its possible
support is enlarged to that box's input interface. Induction gives
\cref{eq:network-cut}. Apply \cref{ip:nosignal}.
\end{proof}

Thus an uncounted control wire, capacity flag, or transport register
that is an ancestor of an event is \emph{inside} its boundary.
If an external geometric decision is a specified function only of
the state functional on that event interface and common declared
labels, equal interface data give the same decision. This last
assertion is substitution into that function, not a claim that the
nonlinear coupling itself is a channel.

An input-dependent initialization or encoding is also part of the
network. Hiding it outside the ancestor calculation would change the
claimed cut.

\subsection{Sharpness in one dimension}

% 17
\begin{proposition}[Relay attaining the scalar bound]
\label{prop:relay}
Let \(R\ge1\) be an integer. On the integer line, with
\(d(i,j)=a\abs{i-j}\), use
\begin{equation}
 B_{t,k}
 =\{k(R+1)+(t-1)R+j:j=0,\ldots,R\},
 \qquad k\in\Z.
 \label{eq:relay-blocks}
\end{equation}
Swap the endpoint factors in each block. A factor initially at \(0\)
is at \(tR\) after \(t\) ticks, attaining speed \(Ra/\tau\).
Every finite-horizon relay has a finite-site realization.
\end{proposition}

\begin{proof}
At each tick the blocks partition the line into consecutive intervals
of diameter \(Ra\). At tick \(t\), the factor is at the left endpoint
\((t-1)R\) of \(B_{t,0}\); the swap sends it to \(tR\), the next
tick's relay left endpoint.

For horizon \(T\), choose a finite interval containing
\(B_{t,0}\) for every \(1\le t\le T\). At each tick retain the
partition blocks wholly contained in that interval and replace
the clipped boundary portions by singleton blocks. The relay
blocks are unchanged. No infinite tensor-product state is needed.
The transported factor may be entangled with a reference.
\end{proof}

\subsection{Retiming fixed gates}

% 18
\begin{definition}[Labelled gate order]
\label{def:gate-order}
Let \(G\) be a finite labelled collection of fixed channels on
reserved interfaces, with supports \(S_g\subseteq X\).
A strict partial order \(<\) is admissible if gates with intersecting
supports are comparable. A legal execution is a linear extension.
\end{definition}

% 19
\begin{theorem}[Retiming invariance]
\label{thm:retiming}
All legal executions of an admissibly ordered labelled gate set
have the same total channel.
\end{theorem}

\begin{proof}
Incomparable gates act on disjoint factors and commute.
Any two linear extensions are connected by adjacent swaps of
incomparable elements: move the first desired differing element
leftwards; every crossed element must be incomparable, since
either comparability would contradict one of the extensions.
Repeat.
\end{proof}

Records and control dependencies belong to supports. The theorem
does not move a gate past a gate using its record, change a geometric
parameter while retaining the same channel label, or establish
no-signalling for nonlinear geometric coupling.

\subsection{Directional propagation}

% 20
\begin{proposition}[Directional obstruction]
\label{prop:directional}
In a prescribed square-lattice model permitting one cardinal step of
length \(a\), or waiting, per tick, the asymptotic velocity set is
\begin{equation}
 \mathcal V=\{(v_x,v_y):\abs{v_x}+\abs{v_y}\le c\},
 \qquad c=a/\tau.
 \label{eq:velocity-diamond}
\end{equation}
An isotropic physical speed \(c_{\mathrm{phys}}=c\) is not dominated
in every direction.
\end{proposition}

\begin{proof}
After \(n\) ticks,
\(\abs{\Delta x}+\abs{\Delta y}\le na\).
Step proportions approximate every point of the displayed diamond.
The velocity \((c/\sqrt2,c/\sqrt2)\) has Euclidean norm \(c\)
but \(\ell^1\)-norm \(\sqrt2c\), so is excluded.
\end{proof}

% 21
\begin{remark}[Conditional kinematics]
\label{rem:conditional-kinematics}
The preceding example concerns cardinal hops, not every partitioned
schedule. This section proves dependency statements on a prescribed
substrate. It neither reconstructs a physical light cone nor
establishes Lorentz invariance.
\end{remark}

\section{Spectator-extension invariance}
\label{sec:spectators}

\subsection{Arbitrary extensions}

An admissible extension to a disjoint spectator interface \(N\)
satisfies
\begin{equation}
 \Tr_N\widetilde\rho_{\Gamma N}=\rho_\Gamma.
 \label{eq:extension}
\end{equation}
It may be entangled. Existing classical wires remain jointly
block diagonal.

% 22
\begin{lemma}[Channels commute with spectator restriction]
\label{lem:trace}
For \(\Psi:L(\cH_\Gamma)\to L(\cH_{\Gamma'})\),
\begin{equation}
 \Tr_N[(\Psi\otimes\id_N)(\widetilde\rho)]
 =\Psi(\Tr_N\widetilde\rho).
 \label{eq:trace-channel}
\end{equation}
\end{lemma}

\begin{proof}
For every output observable \(A\), both sides have expectation
\[
 \Tr((\Psi^*(A)\otimes I_N)\widetilde\rho)
 =\Tr(\Psi^*(A)\Tr_N\widetilde\rho).
\]
\end{proof}

% 23
\begin{theorem}[Spectator-extension invariance]
\label{thm:spectators}
Consider an original certified run
\[
 (q_k;\Gamma_k;\rho_k;\loc_k),\qquad k=0,\ldots,T,
\]
and an initial admissible spectator extension with the same original
geometry, locations, control, and declared resources. Suppose:
\begin{enumerate}
\item original matter maps extend by \(\id_N\);
\item coupling algebras extend by
      \(A\mapsto A\otimes I_N\), or coupling inputs are specified
      functions only of the original reduced state;
\item \cref{ass:sched} holds, including spectator transport and
      separate storage legality;
\item spectator outcomes are neither read nor used during the run.
\end{enumerate}
Then a paired extended run is legal and, at every aligned step,
\begin{equation}
 \widetilde q_k=q_k,
 \qquad
 \Tr_N\widetilde\rho_k=\rho_k.
 \label{eq:spectatorresult}
\end{equation}
Original transports and declared control outputs also agree.
\end{theorem}

\begin{proof}
Induct on the steps. Equal declared inputs select the same command,
guard, support, and certificate.

A geometric rule receives equal geometric and resource labels and
leaves matter unchanged. A matter rule has the common parameter
\(q_k\), and \cref{lem:trace} preserves the reduction identity.
For a coupling rule,
\[
 \Tr((A\otimes I_N)\widetilde\rho_k)=\Tr(A\rho_k)
 \qquad(A\in\cA_v),
\]
so its complete input functional and output agree.
The transport and separate-reservation clauses establish legality
and equality of original locations and control data at each step.
\end{proof}

% 24
\begin{corollary}[Cardinality blindness]
\label{cor:cardinality}
Under all hypotheses of \cref{thm:spectators}, replacing the initial
state by \(\rho_0\otimes\phi_N\), for any finite spectator interface
and normalized \(\phi_N\), leaves the geometric trace unchanged.
\end{corollary}

\begin{proof}
A product insertion is a special case of \cref{eq:extension}.
\end{proof}

The theorem is not restricted to fixed pure spectators. Arbitrary
mixed and input-correlated extensions are covered by the restriction
identity itself. A different isometric construction may require an
explicit preparation purification; such a requirement is not supplied
by merely calling an extra wire a spectator~\cite{CheungEm05A}.

\subsection{The capacity leak}

% 25
\begin{example}[Indirect cardinality observation]
\label{ex:capacityleak}
Let \(q\in\{0,1\}\), and let a geometric rule request \(q\mapsto1\)
subject to the guard
\[
 \abs{\Gamma}\le K.
\]
Coupling algebras may be trivial and every matter operation may avoid
spectators. A run with \(\abs{\Gamma}=K\) permits the update, whereas
adding one spectator blocks it.
\end{example}

The guard is an observation channel in the controller. The example
violates \cref{ass:sched}, not \cref{thm:spectators}.
Repartitioning, queue priority, timing, or a spectator-readable
transport history can produce the same failure.

% 26
\begin{failure}[Undeclared observation]
\label{fail:observation}
The spectator theorem does not apply if geometry, coupling, control,
or certification reads spectator cardinality, spectator state, or
spectator-dependent resource availability through an undeclared input.
\end{failure}

\subsection{Terminal readout and ownership}

Spectators may be returned or consumed by terminal \(\Enter\).
The partial trace in \cref{eq:spectatorresult} describes an observation
interface, not a term-level discard rule.

Nonselective terminal measurement of an entangled spectator preserves
the original reduction. Conditional reductions need not be preserved.
For a Bell pair, conditioning on the spectator's computational-basis
outcome prepares the corresponding pure state on the original factor.
Later geometry using that outcome is a different comparison.

% 27
\begin{remark}[Interpretation]
\label{rem:noninterference}
The theorem specifies a noninterfering rule class, including its
controller. It excludes name cardinality as a source variable within
that class. It does not establish physically correct gravitational
dynamics.
\end{remark}

\section{Restricted destructive deferred readout}
\label{sec:deferred}

Immediate readout destroys \(S\), whereas coherent recording retains
it. Comparison therefore requires a common accessible output.

\subsection{Measurement identities}

% 28
\begin{lemma}[Recording followed by restriction]
\label{lem:copytrace}
For every \(\rho\in D(\cH_{SB})\),
\begin{equation}
 \Tr_S(V\rho V^\dagger)
 =\sum_z\ket z\bra z_A\otimes M_z\rho M_z^\dagger.
 \label{eq:copytrace}
\end{equation}
\end{lemma}

\begin{proof}
Write
\(\rho=\sum_{z,z'}\ket z\bra{z'}_S\otimes\rho_{zz'}\).
Recording gives
\[
 V\rho V^\dagger
 =\sum_{z,z'}\ket z\bra{z'}_S
       \otimes\ket z\bra{z'}_A\otimes\rho_{zz'}.
\]
Tracing \(S\) removes exactly the terms with \(z\ne z'\).
\end{proof}

% 29
\begin{lemma}[Continuation identity]
\label{lem:continuation}
For a channel \(\Lambda:L(\cH_B)\to L(\cH_{B'})\),
\begin{equation}
 \Tr_S\!\left[
 \cN_A((\id_{SA}\otimes\Lambda)(V\rho V^\dagger))
 \right]
 =(\id_R\otimes\Lambda)\cM_S(\rho),
 \label{eq:continuation}
\end{equation}
where \(\cN_A\) destructively reads \(A\) into \(R\).
Outputs are identified using the canonical wire permutation.
\end{lemma}

\begin{proof}
A channel on \(B\) commutes with restriction over \(S\) and readout
of \(A\). Apply \cref{lem:copytrace}; readout of the already
block-diagonal \(A\)-reduction replaces its basis label by \(R\).
\end{proof}

\subsection{Geometry and continuation}

% 30
\begin{theorem}[Restricted destructive deferred readout]
\label{thm:deferred}
Start with common geometry and declared control data and a state
\(\rho\) on \(S\otimes B\). Compare:
\begin{enumerate}
\item immediate \(\Enter_S\), followed by continuation on \(B\);
\item allocation of \(A\), coherent recording, the corresponding
      continuation on \(B\), and terminal \(\Enter_A\).
\end{enumerate}
Between recording or initial readout and terminal carrier readout,
assume:
\begin{enumerate}[label=(D\arabic*)]
\item matter commands act only on the current continuation interface
      \(B_k\), not on \(S,A\), or the immediate record \(R\);
\item coupling inputs and state-dependent guards use only the
      reduction on \(B_k\);
\item geometric rules inspect only declared geometric labels;
\item control, supports, capacities, and transport of continuation
      names are blind to the excluded registers, with separately
      reserved storage as in \cref{ass:sched}.
\end{enumerate}
Then geometric traces coincide at aligned continuation events.
After terminal carrier readout, the deferred output restricted away
from \(S\) equals the immediate output on \(R\otimes B_T\).
\end{theorem}

\begin{proof}
Both initial continuation reductions equal \(\Tr_S\rho\):
\[
 \Tr_R\cM_S(\rho)=\Tr_S\rho,
 \qquad
 \Tr_{SA}(V\rho V^\dagger)=\Tr_S\rho.
\]
Induction using (D1)--(D4) gives common commands, guards, geometry,
continuation transports, and reductions at every event.
For this fixed input, compose the matter channels selected along
the common trace into \(\Lambda\). They act only on the continuation
interface. Equation~\eqref{eq:continuation} gives equality of the
complete common record--matter output.
\end{proof}

% 31
\begin{remark}[Input-dependent selection]
\label{rem:selected-channel}
The selected \(\Lambda\) may depend on the input through nonlinear
geometric selection. The proof is an equality for each compared pair,
not a claim that the complete coupled input--output map is linear.
\end{remark}

% 32
\begin{remark}[Output typing]
\label{rem:output-typing}
The immediate output has type \(\Bit^{\otimes n}\otimes B_T\).
The deferred output additionally contains \(S\). It must be returned
or consumed by a well-typed continuation. Inaccessibility does not
create a weakening rule.
\end{remark}

% 33
\begin{example}[Access to excluded registers]
\label{ex:excluded-registers}
An operation on retained \(S\) has no immediate destructive
counterpart. Reading \(R\) during continuation may permit a larger
coherent-control construction, but not this theorem.
Coupling to the coherent joint state on \(S\otimes A\) can
distinguish recording from destructive readout.
\end{example}

Changing a carrier does not create a missing observation channel.
In particular, coherent recording and later destructive carrier
readout do not authorize access to retained \(S\) or a spectator.
This is the observation-boundary refusal compared with
Cheung's carrier-obstruction record~\cite{CheungPsy03D}.
The present theorem proves the restricted identity; it does not
assert universal equivalence of immediate and deferred measurement.

\section{External conical geometry and certified local moves}
\label{sec:geometry}

This section supplies an external holonomy witness, a static gauge
flip, and one compactly attached four-face adjacency exchange.
The ambient metric and resting particle neighbourhood remain fixed.
The moving patch has nontrivial adapted-frame transitions but trivial
contractible spacetime holonomy.

\subsection{Cone charts and overlap components}

Use
\[
 \eta=\operatorname{diag}(-1,1,1),\qquad
 0<\mu<2\pi,\qquad
 \alpha=1-\frac{\mu}{2\pi}.
\]
On the punctured cone,
\begin{equation}
 ds^2=-dT^2+dr^2+\alpha^2r^2d\theta^2,\qquad r>0,
 \label{eq:cone-metric}
\end{equation}
with \(\theta\) periodic modulo \(2\pi\).
Its completion has a timelike conical axis. The spinless
point-particle interpretation is standard~\cite{DeserJackiwHooft1984};
no field equation is derived.

On the universal cover,
\[
 D(T,r,\widetilde\theta)
 =(T,r\cos(\alpha\widetilde\theta),
       r\sin(\alpha\widetilde\theta)).
\]
For the deck transformation
\(\mathsf T(T,r,\widetilde\theta)
=(T,r,\widetilde\theta+2\pi)\), define
\begin{equation}
 R(\mu)=
 \begin{pmatrix}
 1&0&0\\
 0&\cos\mu&-\sin\mu\\
 0&\sin\mu&\cos\mu
 \end{pmatrix}.
 \label{eq:rotation}
\end{equation}
Then
\begin{equation}
 D\circ\mathsf T^{-1}=R(\mu)\circ D.
 \label{eq:developing}
\end{equation}

Choose \(0<\epsilon<\pi/4\), with angular lifts
\[
 U_1=(-\epsilon,\pi+\epsilon),\qquad
 U_2=(\pi-\epsilon,2\pi+\epsilon),
\]
restricted where necessary to injective developing charts.
Their two overlap components have transitions
\begin{equation}
 \Lambda_{2\leftarrow1}^{\pi}=I,
 \qquad
 \Lambda_{1\leftarrow2}^{0}=R(\mu).
 \label{eq:seam-transitions}
\end{equation}
The positively oriented particle word is
\begin{equation}
 (\Lambda_{1\leftarrow2}^{0},0)
 (\Lambda_{2\leftarrow1}^{\pi},0)
 =(R(\mu),0).
 \label{eq:particle-word}
\end{equation}
Overlap-component indexing prevents suppression of the nontrivial
seam. No smooth flat chart contains the axis.

\subsection{Tangent holonomy}

% 34
\begin{lemma}[Developing holonomy and tangent transport]
\label{lem:soldering}
Suppose
\begin{equation}
 D\circ\mathsf T_\gamma^{-1}=h_\gamma\circ D,
 \qquad h_\gamma(y)=L_\gamma y+b_\gamma.
 \label{eq:affine-development}
\end{equation}
With this convention, parallel transport around \(\gamma\), in the
starting developed frame, has matrix \(L_\gamma\).
\end{lemma}

\begin{proof}
Lift the loop from \(\widetilde x\) to
\(\mathsf T_\gamma\widetilde x\).
Flat developed transport keeps the Minkowski vector constant:
\[
 dD_{\mathsf T_\gamma\widetilde x}(v')
 =dD_{\widetilde x}(v).
\]
Endpoint identification uses \(d\mathsf T_\gamma^{-1}\).
Differentiating \cref{eq:affine-development} gives
\[
 dD_{\widetilde x}\,d\mathsf T_\gamma^{-1}(v')
 =L_\gamma dD_{\mathsf T_\gamma\widetilde x}(v')
 =L_\gamma dD_{\widetilde x}(v).
\]
\end{proof}

The cone word acts on spacetime tangent vectors, not an unrelated
internal fibre. Developments and their connection data must remain
distinct~\cite{Kadar2005}.

\subsection{Deficit and particle--slice data}

% 35
\begin{lemma}[Axis and trace information]
\label{lem:axis}
For \(L=C R(\mu)C^{-1}\), \(C\in\Lor\), and \(0<\mu<2\pi\),
\begin{equation}
 \Fix(L)=\R C e_0,\qquad p_L=C e_0,\qquad e_0=(1,0,0).
 \label{eq:particle-axis}
\end{equation}
The future unit fixed vector is unique, and
\[
 \Tr L=1+2\cos\mu.
\]
The trace alone does not distinguish \(\mu\) from \(2\pi-\mu\).
\end{lemma}

\begin{proof}
The spatial rotation has no nonzero fixed vector in its spatial
plane. Conjugation preserves trace and future orientation and carries
the fixed line to \(\R C e_0\).
\end{proof}

For an oriented orthonormal basis \((u,v)\) of \(p_L^\perp\), with
\((p_L,u,v)\) positively oriented,
\[
 \cos\mu=\eta(u,Lu),\qquad
 \sin\mu=\eta(v,Lu)
\]
recover the oriented deficit. For a spacelike piece with future
unit normal \(n\), set
\begin{equation}
 \chi(p,n)=\arccosh(-\eta(p,n)).
 \label{eq:rapidity}
\end{equation}
Both vectors must be expressed in the same development.

% 36
\begin{proposition}[Gauge invariance of marked-slice data]
\label{prop:slice-invariance}
The oriented deficit and \(\chi(p,n)\) are invariant under proper,
time-orientation-preserving chart changes. Rapidity is an invariant
of the particle together with the marked slice piece, not of the
particle alone.
\end{proposition}

\begin{proof}
A chart change simultaneously conjugates \(L\) and transforms
\(p,u,v,n\), preserving the orientations and inner products.
\end{proof}

\subsection{Equal name data, unequal marked-slice data}

Choose \(k\ge3\) and
\[
 \vartheta=\frac{2\pi-\mu}{k}<\pi,\qquad
 u_j=\left(
 \cos((j+\tfrac12)\vartheta),
 \sin((j+\tfrac12)\vartheta)\right).
\]
On sector \([j\vartheta,(j+1)\vartheta]\), let
\(\beta=\tanh\zeta\) and set
\begin{equation}
 T=\beta\,u_j\cdot x.
 \label{eq:fan}
\end{equation}
The future unit normal is
\[
 n_j=\cosh\zeta\,e_0+\sinh\zeta\,(0,u_j).
\]
On a shared ray, both functions have value
\(\beta r\cos(\vartheta/2)\); the wedge faces match similarly.
The result is a continuous piecewise-flat spacelike neighbourhood.
Joining equal-radius ray endpoints by straight chords gives a finite
polygonal star.

% 37
\begin{proposition}[A witness invisible to name data]
\label{prop:fan-witness}
Attach identical matter interfaces, states, and abstract cell
assignments to the resting fan and to \cref{eq:fan} with
\(\zeta\ne0\). Their particle holonomy is the same, but
\begin{equation}
 \chi(e_0,n_j)=
 \begin{cases}
 0,&\text{resting fan},\\
 \abs{\zeta},&\text{tilted fan}.
 \end{cases}
 \label{eq:fan-rapidity}
\end{equation}
\end{proposition}

\begin{proof}
The relevant inner products are \(1\) and \(\cosh\zeta\), and
\(\arccosh(\cosh\zeta)=\abs{\zeta}\).
\end{proof}

An arbitrary globally boosted plane need not descend through the
cone identification. The sectorwise construction avoids that
assumption. It does not identify rapidity with stress energy.

\subsection{Affine intersection laws}

% 38
\begin{proposition}[Constraint words and affine edge lengths]
\label{prop:affine}
A polygonal slice induced from a fixed flat conical spacetime and
its component-indexed atlas has ordered transition products equal
to the corresponding monodromies.

On an interval of fixed incidence, suppose normals are constant,
offsets are affine in the parameter, and endpoints solve nonsingular
constant-coefficient linear intersection systems. If an edge has a
fixed spacelike direction, its length is affine on subintervals
where orientation does not reverse.
\end{proposition}

\begin{proof}
The first statement is chart continuation. An endpoint satisfying
\(Az=b_0+s b_1\), with \(A\) constant and invertible, is affine.
An edge difference with fixed unit spacelike direction is
\((c_0+s c_1)e\), of length \(\abs{c_0+s c_1}\).
\end{proof}

Affine endpoint motion alone does not make arbitrary segment lengths
affine. Artificial subdivision edges are checked explicitly below.
No estimate is continued through an event merely by assuming
regular-stratum smoothness.

\subsection{A static square gauge flip}
\label{sec:square}

Set \(\mu=\pi/2\). In a nonsingular developed sector take
\[
 a=(0,3,1),\quad b=(0,4,1),\quad
 c=(0,4,2),\quad d=(0,3,2).
\]
They bound a unit square with a matching certified exterior.

\begin{center}
\begin{tabularx}{\textwidth}{@{}lXX@{}}
\toprule
Field & Before & After\\
\midrule
Faces & \(abc,acd\) & \(abd,bcd\)\\
Boundary & \(ab,bc,cd,da\) & unchanged\\
Internal edge & \(ac\) & \(bd\)\\
Boundary lengths & \(1,1,1,1\) & unchanged\\
Internal length & \(\sqrt2\) & \(\sqrt2\)\\
Patch affine transitions & \((I,0)\) & \((I,0)\)\\
Particle labels in patch & none & none\\
Mode & \(m=0\) & \(m=1\)\\
Permission & \(\kappa\ge1\) & \(\kappa-1\)\\
\bottomrule
\end{tabularx}
\end{center}

% 39
\begin{definition}[Square guard and transport]
\label{def:square-guard}
The guard is \(m=0\), \(\kappa\ge1\), and membership in the fixed square
family. Names on the old interior faces or diagonal move to the
designated successor \(abd\). Boundary and exterior labels are
retained. No matter channel or coupling fires.
\end{definition}

% 40
\begin{proposition}[Square certificate]
\label{prop:square}
The update is a certified \((G)\)-rule preserving the metric, marked
resting slice, and vertex monodromies. Particle deficit and rapidity
remain \(\pi/2\) and \(0\).
\end{proposition}

\begin{proof}
Both triangulations cover the same square and boundary. Every internal
transition word is \((I,0)\). The particle word remains
\((R(\pi/2),0)(I,0)\), with axis and resting normal \(e_0\).
\end{proof}

This constant-length gauge flip is not an edge-collapse exchange.
Its guard and permission accounting are spectator-blind.

\subsection{Four affine faces}
\label{sec:fourfaces}

Let \(s=0\) be the event. In a common chart \(z=(T,x,y)\), choose
\[
 0<q<p<1,\qquad
 a=\sqrt{1-p^2},\quad b=\sqrt{1-q^2},\quad \Delta=b-a>0,
\]
and define
\begin{equation}
 \begin{aligned}
 f_E&=px+as,& f_W&=-px+as,\\
 f_N&=qy+bs,& f_S&=-qy+bs,
 \end{aligned}
 \qquad
 F_s=\max\{f_E,f_W,f_N,f_S\}.
 \label{eq:fourplanes}
\end{equation}
An active face attains the maximum; its interior is the strict-maximum
region. The concrete certificate uses
\begin{equation}
 p=\frac35,\quad q=\frac5{13},\quad
 a=\frac45,\quad b=\frac{12}{13},\quad \Delta=\frac8{65}.
 \label{eq:rational}
\end{equation}

% 41
\begin{proposition}[Spacelike graph and time order]
\label{prop:R1}
The graph of \(F_s\) is continuous, piecewise affine, and
\(p\)-Lipschitz with \(p<1\). Every face is spacelike. For \(s_2>s_1\),
\begin{equation}
 F_{s_2}(x,y)-F_{s_1}(x,y)\ge a(s_2-s_1)>0.
 \label{eq:time-ordering}
\end{equation}
\end{proposition}

\begin{proof}
The spatial gradients have norm \(p\) or \(q\); their maximum
retains the common Lipschitz bound. A face tangent satisfies
\[
 \eta((v_i\cdot u,u),(v_i\cdot u,u))
 =\abs u^2-(v_i\cdot u)^2>0
\]
for \(u\ne0\). Every face function increases by at least
\(a(s_2-s_1)\), so their maximum does too.
\end{proof}

% 42
\begin{proposition}[Incoming edge]
\label{prop:R2}
For \(s<0\), \(E,W\) share exactly
\begin{equation}
 x=0,\quad
 \abs y\le\frac{\Delta(-s)}q,\quad T=as.
 \label{eq:incoming-edge}
\end{equation}
Its endpoints are \(EWN,EWS\), and its length is
\begin{equation}
 \ell_-(s)=\frac{2\Delta}{q}(-s)=\frac{16}{25}(-s).
 \label{eq:incominglength}
\end{equation}
\end{proposition}

\begin{proof}
Equality gives \(x=0\). Dominance requires
\(as\ge q\abs y+bs\), hence \(q\abs y\le-\Delta s\).
The two equalities at its endpoints add \(N\) or \(S\).
The displacement is purely in the \(y\)-direction.
\end{proof}

% 43
\begin{proposition}[Outgoing edge]
\label{prop:R3}
For \(s>0\), \(N,S\) share exactly
\begin{equation}
 y=0,\quad
 \abs x\le\frac{\Delta s}p,\quad T=bs.
 \label{eq:outgoing-edge}
\end{equation}
Its endpoints are \(NSE,NSW\), and its length is
\begin{equation}
 \ell_+(s)=\frac{2\Delta}{p}s=\frac{16}{39}s.
 \label{eq:outgoinglength}
\end{equation}
\end{proposition}

\begin{proof}
Equality gives \(y=0\); dominance requires
\(p\abs x\le\Delta s\). The displacement is purely spatial.
\end{proof}

% 44
\begin{proposition}[A junction, not a patch collapse]
\label{prop:R4}
At \(s=0\), all four planes meet at the origin and the central lengths
vanish, but every face contains a two-dimensional open region.
The incidence change is
\begin{equation}
 \{EWN,EWS\}\longrightarrow\{EWNS\}
 \longrightarrow\{NSE,NSW\}.
 \label{eq:exchange-incidence}
\end{equation}
\end{proposition}

\begin{proof}
Here \(F_0=\max\{p\abs x,q\abs y\}\).
For example, \(E\) is strict on \(x>0,\ px>q\abs y\).
The other regions follow by symmetry; the four-way intersection
is only the origin.
\end{proof}

% 45
\begin{proposition}[Transversality and isolation]
\label{prop:R5}
The central one-sided derivatives are
\begin{equation}
 \dot\ell_-(0^-)=-2\Delta/q<0,\qquad
 \dot\ell_+(0^+)=2\Delta/p>0.
 \label{eq:transversality}
\end{equation}
Mixed adjacencies \(EN,ES,WN,WS\) persist. No other core pair
exchanges a positive-length edge near the event.
\end{proposition}

\begin{proof}
Differentiate the central laws. In each quadrant a mixed adjacency
lies on
\[
 p\abs x-q\abs y=\Delta s
\]
and extends from a central triple junction to the exterior.
The only remaining pairs are \(EW\) and \(NS\), already calculated.
\end{proof}

The exchange is determined by the declared maximum slicing rule.
It is not a uniqueness theorem over all foliations.

\paragraph{Adapted frames.}
For a slope \(v_i\), choose a Lorentz map with time coordinate
\[
 X_i^0=\frac{T-v_i\cdot(x,y)}{\sqrt{1-\abs{v_i}^2}}.
\]
On its face this equals \(s\). The concrete maps are
\begin{equation}
 \begin{aligned}
 C_E&=\begin{pmatrix}
 5/4&-3/4&0\\-3/4&5/4&0\\0&0&1
 \end{pmatrix},
 &
 C_W&=\begin{pmatrix}
 5/4&3/4&0\\3/4&5/4&0\\0&0&1
 \end{pmatrix},\\
 C_N&=\begin{pmatrix}
 13/12&0&-5/12\\0&1&0\\-5/12&0&13/12
 \end{pmatrix},
 &
 C_S&=\begin{pmatrix}
 13/12&0&5/12\\0&1&0\\5/12&0&13/12
 \end{pmatrix}.
 \end{aligned}
 \label{eq:boosts}
\end{equation}
They are proper future-preserving Lorentz maps. Set
\begin{equation}
 \Lambda_{i\leftarrow j}=C_iC_j^{-1}.
 \label{eq:core-transitions}
\end{equation}
The opposite-pair entries are
\begin{equation}
 \Lambda_{E\leftarrow W}
 =\begin{pmatrix}17/8&-15/8&0\\-15/8&17/8&0\\0&0&1\end{pmatrix},
 \qquad
 \Lambda_{N\leftarrow S}
 =\begin{pmatrix}97/72&0&-65/72\\0&1&0\\-65/72&0&97/72\end{pmatrix}.
 \label{eq:opposite-transitions}
\end{equation}
For \(X_+=E,X_-=W,Y_+=N,Y_-=S\),
\begin{equation}
 \Lambda_{X_\epsilon\leftarrow Y_\nu}
 =
 \begin{pmatrix}
 65/48&-\epsilon\,3/4&\nu\,25/48\\
 -\epsilon\,13/16&5/4&-\epsilon\nu\,5/16\\
 \nu\,5/12&0&13/12
 \end{pmatrix}.
 \label{eq:mixedtransitions}
\end{equation}
Reverse maps are inverses; all core translations are zero.

% 46
\begin{proposition}[Exact ordered products]
\label{prop:R6}
Every closed contractible core word is the affine identity.
In particular,
\begin{align}
 \Lambda_{E\leftarrow W}\Lambda_{W\leftarrow N}
       \Lambda_{N\leftarrow E}&=I,
 &
 \Lambda_{E\leftarrow W}\Lambda_{W\leftarrow S}
       \Lambda_{S\leftarrow E}&=I,
 \label{eq:incoming-products}\\
 \Lambda_{N\leftarrow S}\Lambda_{S\leftarrow E}
       \Lambda_{E\leftarrow N}&=I,
 &
 \Lambda_{N\leftarrow S}\Lambda_{S\leftarrow W}
       \Lambda_{W\leftarrow N}&=I.
 \label{eq:outgoing-products}
\end{align}
The event four-face word is also \(I\).
\end{proposition}

\begin{proof}
Every word telescopes:
\[
 (C_{i_0}C_{i_1}^{-1})\cdots
 (C_{i_{m-1}}C_{i_0}^{-1})=I.
\]
\end{proof}

Nontrivial adapted transitions here are frame changes in one flat
development, not evidence of spacetime curvature.

\subsection{Compact collar and frozen exterior}
\label{sec:collar}

For \(-1\le s\le1\) and \(H=2\), define
\begin{equation}
 g_s(x,y)=\min\{F_s(x,y),H+s\}.
 \label{eq:capped}
\end{equation}
The uncapped interior region is
\begin{equation}
 \mathscr R_s=[-X_s,X_s]\times[-Y_s,Y_s],
 \qquad X_s=\frac{10+s}{3},\quad Y_s=\frac{26+s}{5},
 \label{eq:inner-rectangle}
\end{equation}
since \(F_s\le H+s\) is equivalent to these two inequalities.
Choose
\begin{equation}
 K=[-R_x,R_x]\times[-R_y,R_y],
 \qquad R_x=\frac{14}{3},\quad R_y=6.
 \label{eq:K}
\end{equation}
Then
\begin{equation}
 R_x-X_s=\frac{4-s}{3}>0,\qquad
 R_y-Y_s=\frac{4-s}{5}>0.
 \label{eq:collar-margins}
\end{equation}

% 47
\begin{proposition}[Spacelike capped slices]
\label{prop:cap}
The capped graph is continuous, piecewise flat, and \(p\)-Lipschitz.
It agrees with \(T=H+s\) near \(\partial K\), and retains the lower
time increment \(a(s_2-s_1)\).
Both central edge laws remain unchanged in the window.
\end{proposition}

\begin{proof}
Minimum and maximum preserve a common Lipschitz bound and a common
lower time increment. Strict collar margins give the resting boundary
neighbourhood. The incoming central height margin is
\[
 H+s-as=2+s/5\ge9/5;
\]
the outgoing margin is
\[
 H+s-bs=2+s/13\ge25/13.
\]
Thus the cap does not clip the central edges.
\end{proof}

\paragraph{Finite collar cells.}
There are four core faces and four resting collar polygons.
The north-east collar has spatial vertices
\begin{equation}
 (X_s,0),\ (R_x,0),\ (R_x,R_y),\
 (0,R_y),\ (0,Y_s),\ (X_s,Y_s),
 \label{eq:collar-hexagon}
\end{equation}
all at \(T=H+s\). Reflections, with boundary order reversed when
needed, give the other counterclockwise polygons.
Inner and outer side midpoints divide each rectangle boundary
into eight segments.

At an inner corner, two core faces and one collar face meet.
At an inner midpoint, one core face and two coplanar collar
subdivisions meet. These subdivisions have fixed incidence and
are not additional transitions.

The collar chart is
\begin{equation}
 A_0(z)=(I,-H e_0)z=(T-H,x,y).
 \label{eq:collar-chart}
\end{equation}
Core-to-collar transitions are
\begin{equation}
 A_0(C_i,0)^{-1}=(C_i^{-1},-H e_0).
 \label{eq:core-collar-transition}
\end{equation}
For affine pairs,
\begin{equation}
 (L,b)(L',b')=(LL',Lb'+b).
 \label{eq:affine-multiplication}
\end{equation}

% 48
\begin{proposition}[Collar words and polygon closure]
\label{prop:collarproducts}
Collar and mixed vertex words are the affine identity.
All polygons close, and matching edges have equal induced lengths.
\end{proposition}

\begin{proof}
All cell charts are globally defined affine isometries \(A_i\)
of the same patch; transitions \(A_iA_j^{-1}\) telescope.
The core polygons are intersections of their declared half-spaces
with \(\mathscr R_s\), and the collar polygons have the listed
boundaries. Shared endpoints and segments are identical.
\end{proof}

\paragraph{Attachment to the cone.}
Use the wedge of angle \(3\pi/2\), and translate the patch by
\[
 (X,Y)=(20+x,20+y).
\]
The entire \(K\) lies inside its first quadrant, away from axis
and seam. Set \(T=H+s\) on the rest of the cone.

For an explicit finite exterior construction, divide the wedge
into its three convex quadrants. In the first quadrant cut by the
vertical lines through \(20-R_x,20,20+R_x\) and the horizontal lines
through \(20-R_y,20,20+R_y\). Retain the cells outside the translated
\(K\), and replace its interior by the eight patch cells.
This finite line arrangement matches the eight boundary segments.
Unbounded exterior cells and rays are permitted and remain fixed.

Shift the cone development to
\[
 D_H=(T-H,r\cos(\alpha\widetilde\theta),
           r\sin(\alpha\widetilde\theta)).
\]
The time shift commutes with \(R(\mu)\).
The collar-to-exterior transition is
\begin{equation}
 (I,(0,20,20)).
 \label{eq:exterior-transition}
\end{equation}

% 49
\begin{proposition}[Boundary matching and particle word]
\label{prop:R8}
Incoming and outgoing descriptions use the same boundary labels,
constant spatial boundary vertices and lengths, resting boundary
plane \(T-H=s\), and fixed exterior transitions.
The cone metric, exterior incidence, and resting particle
neighbourhood are not rewritten. The particle word remains
\begin{equation}
 (R(\pi/2),0)(I,0)=(R(\pi/2),0).
 \label{eq:frozen-particle-word}
\end{equation}
\end{proposition}

\begin{proof}
The cap is resting near \(\partial K\); all its boundary data and
charts are common. A particle loop can be chosen in the unchanged
axis neighbourhood. A path through the patch instead has a
telescoping word determined by its endpoint charts, independent
of its internal incidence.
\end{proof}

Frozen exterior means unchanged geometric and affine-time laws,
not frozen spacetime time coordinates.

\paragraph{Complete core polygon boundaries.}
Write
\[
 U_\nu=(as,0,\nu\Delta(-s)/q)\quad(s<0),\qquad
 Z_\epsilon=(bs,\epsilon\Delta s/p,0)\quad(s>0),
\]
and
\[
 V_{\epsilon,\nu}=(H+s,\epsilon X_s,\nu Y_s),
\quad
 M^x_\epsilon=(H+s,\epsilon X_s,0),
\quad
 M^y_\nu=(H+s,0,\nu Y_s).
\]
Counterclockwise incoming boundaries are
\[
 \begin{aligned}
 E&:\ U_-,V_{+,-},M^x_+,V_{+,+},U_+,\\
 N&:\ U_+,V_{+,+},M^y_+,V_{-,+}.
 \end{aligned}
\]
The outgoing boundaries are
\[
 \begin{aligned}
 E&:\ Z_+,V_{+,-},M^x_+,V_{+,+},\\
 N&:\ Z_-,Z_+,V_{+,+},M^y_+,V_{-,+}.
 \end{aligned}
\]
Reflecting and reversing order gives \(W,S\).
At \(s=0\), the central vertices coincide; remove repeated consecutive
vertices in the geometric realization.

The remaining vertices are the four outer corners
\((H+s,\epsilon R_x,\nu R_y)\) and four outer side midpoints
\((H+s,\epsilon R_x,0)\), \((H+s,0,\nu R_y)\).

Each mixed arm ends at \(V_{\epsilon,\nu}\), and has length
\begin{equation}
 L_{\mathrm{arm}}(s)=
 \begin{cases}
 \dfrac{10+s}{75}\sqrt{1921},&-1\le s\le0,\\[4pt]
 \dfrac{26+s}{195}\sqrt{1921},&0\le s\le1.
 \end{cases}
 \label{eq:arms}
\end{equation}
The two event values agree.

% 50
\begin{proposition}[All lengths and no peripheral collapse]
\label{prop:alllengths}
The complete bounded patch lengths are in
\cref{tab:certificate}. Every noncentral actual edge has length
greater than \(1/2\) throughout the window. All eight faces remain
two-dimensional. The central exchange is the only incidence event.
\end{proposition}

\begin{proof}
The north-east incoming arm displacement is
\(X_s(p,1,p/q)\), of spacelike norm
\(X_s\sqrt{1921}/25\).
The outgoing displacement is \(Y_s(q,q/p,1)\), of norm
\(Y_s\sqrt{1921}/39\). Reflection gives the other arms.

Resting lengths are \(X_s,Y_s,(4-s)/3,(4-s)/5,R_x,R_y\).
Their minimum is \(3/5\); arm lengths are at least
\(3\sqrt{1921}/25>1/2\).
Each core face has a strict-maximum neighbourhood immediately
inside its inner side midpoint. Every collar polygon has nonempty
interior by the strict margins. Central endpoints remain strictly
inside \(\mathscr R_s\), and all peripheral incidence is fixed.
\end{proof}

\begin{table}[p]
\centering
\small
\begin{tabularx}{\textwidth}{@{}p{.24\textwidth}XXX@{}}
\toprule
Field & Incoming & Event & Outgoing\\
\midrule
Core faces & \(E,W,N,S\) & same & same\\
Collar faces & four hexagons & same & same\\
Central adjacency & \(EW\) & four-face point & \(NS\)\\
Central triples & \(EWN,EWS\) & common junction & \(NSE,NSW\)\\
Central length & \(16(-s)/25\) & \(0\) & \(16s/39\)\\
Four arms &
\(\frac{10+s}{75}\sqrt{1921}\) &
\(\frac{2}{15}\sqrt{1921}\) &
\(\frac{26+s}{195}\sqrt{1921}\)\\
Four horizontal cap segments & \(X_s\) & \(10/3\) & \(X_s\)\\
Four vertical cap segments & \(Y_s\) & \(26/5\) & \(Y_s\)\\
Two horizontal collar joins & \((4-s)/3\) & \(4/3\) & \((4-s)/3\)\\
Two vertical collar joins & \((4-s)/5\) & \(4/5\) & \((4-s)/5\)\\
Four outer horizontal segments & \(14/3\) & \(14/3\) & \(14/3\)\\
Four outer vertical segments & \(6\) & \(6\) & \(6\)\\
Core charts & \cref{eq:boosts} & unchanged & unchanged\\
Core transitions & \(C_iC_j^{-1}\) & same table & new incidence\\
Collar transitions & \(A_iA_j^{-1}\) & unchanged & unchanged\\
Boundary transitions & fixed & fixed & fixed\\
Particle labels & \((\pi/2,e_0)\) & unchanged & unchanged\\
Mode & \(0\) & \(0\to1\) & \(1\)\\
Permission & \(k\ge1\) & \(k\to k-1\) & \(k-1\)\\
\bottomrule
\end{tabularx}
\caption{Complete affected bounded data; the fixed exterior completes
the configuration. A regular patch has 18 vertices, 25 edges, and
8 faces. The event realization has 17 vertices and 24 edges.
Two stored central slots give 26 length reports.}
\label{tab:certificate}
\end{table}

\begin{table}[htbp]
\centering
\small
\setlength{\tabcolsep}{4pt}
\begin{tabular}{@{}lccccc@{}}
\toprule
Length & \(-1\) & \(-1/2\) & \(0\) & \(1/2\) & \(1\)\\
\midrule
Active central & \(16/25\) & \(8/25\) & \(0\) & \(8/39\) & \(16/39\)\\
Arm/\(\sqrt{1921}\) &
\(3/25\) & \(19/150\) & \(2/15\) & \(53/390\) & \(9/65\)\\
\(X_s\) & \(3\) & \(19/6\) & \(10/3\) & \(7/2\) & \(11/3\)\\
\(Y_s\) & \(5\) & \(51/10\) & \(26/5\) & \(53/10\) & \(27/5\)\\
\((4-s)/3\) & \(5/3\) & \(3/2\) & \(4/3\) & \(7/6\) & \(1\)\\
\((4-s)/5\) & \(1\) & \(9/10\) & \(4/5\) & \(7/10\) & \(3/5\)\\
Outer horizontal & \(14/3\) & \(14/3\) & \(14/3\) & \(14/3\) & \(14/3\)\\
Outer vertical & \(6\) & \(6\) & \(6\) & \(6\) & \(6\)\\
\bottomrule
\end{tabular}
\caption{Exact reference snapshots. Report words are derived from
these laws, not independent exact geometric labels.}
\label{tab:snapshots}
\end{table}

\subsection{Event germs, guard, transport, and finite code}
\label{sec:finite}

Let \(\cQ_-\) be the regular incoming family for \(-1\le s<0\),
and \(\cQ_+\) the outgoing family for \(0<s\le1\).
Their certified event germs are \(\cQ_0^-,\cQ_0^+\).
Both realize the same capped surface at \(s=0\).

An incoming germ retains the collapsed \(EW\) slot and its coincident
endpoint labels. The outgoing germ retains the born \(NS\) slot and
outgoing endpoint metadata. These descriptions have the common
four-face junction as their geometric quotient.

The semantic event rule is
\begin{equation}
 G_B:\cQ_0^-\longrightarrow\cQ_0^+.
 \label{eq:event-rule}
\end{equation}
It changes mode, permission, and central incidence, but does not
advance \(s\). Continuous within-epoch evolution is a separate
operation.

% 51
\begin{definition}[Exact event guard]
\label{def:guard}
On the declared family, the guard is
\begin{equation}
 \mode=0,\qquad \perm\ge1,\qquad s=0,
 \label{eq:event-guard}
\end{equation}
with the fixed no-other-event certificate of
\cref{prop:alllengths}.
\end{definition}

\paragraph{Abstract location transport.}
No active physical matter is placed inside \(K\).
Inaccessible spectators may nevertheless carry its abstract labels.
For the incoming central edge \(c_-\), endpoints \(j_N,j_S\), and
outgoing central edge \(c_+\), set
\begin{equation}
 \tau_B(c_-)=\tau_B(j_N)=\tau_B(j_S)=c_+.
 \label{eq:transport}
\end{equation}
Every persistent label retains its name.
Fresh outgoing endpoint labels are part of the outgoing description.
All central labels realize the same event point; equivalently,
transport factors through one junction label \(J_0\).

The location map does not encode a developed position.
No stress-energy transport, matter channel, measurement, or coupling
occurs at the event.

% 52
\begin{proposition}[Geometric rule and blind control]
\label{prop:Gcertificate}
The event is a certified \((G)\)-rule. Its guard, support selection,
output geometry, and permission accounting use only declared
geometric and control data. Transport is the fixed map \(\tau_B\),
independent of state and name cardinality.
Under separately reserved spectator location/history storage,
\cref{ass:sched} holds.
\end{proposition}

\begin{proof}
The preceding geometric propositions certify the outgoing germ and
continuation. The guard reads only \(s,\mode,\perm\) and the fixed
family certificate. Applying a fixed label map does not depend on
how many names are transported. Separate reservation prevents
additional spectator storage from changing the geometric budget.
\end{proof}

\paragraph{Exact parameter, approximate reports.}
If an incoming length is \(\ell_-=v(-s)\), floor quantization with
step \(h\) reports zero throughout
\begin{equation}
 0\le -s<h/v.
 \label{eq:premature-zero}
\end{equation}
A zero-length-word guard therefore need not detect the event.

Instead, either an external exact clock supplies \(s=0\), or the
finite code stores
\begin{equation}
 s=j\,2^{-d},\qquad -2^d\le j\le2^d,
 \label{eq:exact-clock}
\end{equation}
with \(d\ge0\) and a signed \((d+2)\)-bit word. The guard tests
\(j=0\).

For fractional precision \(b\ge1\), an unsigned \((b+4)\)-bit word
reports
\begin{equation}
 \widehat L_b=2^{-b}\lfloor2^bL\rfloor,
 \qquad 0\le L-\widehat L_b<2^{-b}.
 \label{eq:length-reports}
\end{equation}
Every displayed length is less than \(16\).
Both central report slots are zero at the event.
The inactive slot is retained; it is not an erased wire.

The decoder reconstructs exact geometry from the family identifier,
rational constants, mode, and exact \(s\). Reports are checked auxiliary
numerical data. Irrational arm lengths are decoded from
\cref{eq:arms}; on a fixed finite parameter grid their reports are
computable by exact comparisons of squared rational numbers.

\paragraph{Finite tables and domains.}
The fixed table contains the four \(C_i\), collar chart, prescribed
transition words, exterior translations, and \(R(\pi/2)\).
All entries have rational coefficients. Arbitrary group closure is
not asserted.

The exchange code contains 26 report words, one mode bit, an
\(r\)-bit permission word with \(r\ge1\), the exact parameter word,
and fixed identifiers. The square code has five reports, mode,
permission, and fixed identifiers.

For a fixed named interface of size \(n\), encode every location in
an \(\ell\)-bit word covering the finite union of input and output
labels. Add an initially zero \(\ell\)-bit history word per name.
Invalid labels and inconsistent reports lie outside the forward
decoder domain.

% 53
\begin{lemma}[Injective event encoding]
\label{lem:injection}
Let \(x\) be a tuple of valid input locations and \(\tau(x)\) its
transported tuple. For \(1\le k\le2^r-1\), valid event reports, and
zero history, the map
\begin{equation}
 \begin{aligned}
 &(0,k,j=0,\mathrm{reports},x,0_{\mathrm{hist}})\\
 &\hspace{8mm}\longmapsto
 (1,k-1,j=0,\mathrm{reports},\tau(x),x_{\mathrm{hist}})
 \end{aligned}
 \label{eq:encodedmap}
\end{equation}
is injective and has disjoint input and output sets.
\end{lemma}

\begin{proof}
History determines \(x\), and the output counter determines \(k\).
All other input data are retained. Modes separate the two sets.
\end{proof}

For the square, use its transport and omit the parameter.
Its five length reports also remain unchanged.

% 54
\begin{proposition}[Decoder-correct event permutation]
\label{prop:decoder}
Exchange every valid forward input in \cref{eq:encodedmap} with its
specified output and fix every other basis string.
This defines a permutation \(U_B\) of the full finite code space.
On its declared forward precondition,
\begin{equation}
 \Dec(U_Bc)=G_B(\Dec(c)).
 \label{eq:decoder}
\end{equation}
This includes geometry, permission, germ incidence, and original
location transport. History is returned as storage.
The square has an analogous permutation \(U_A\).
\end{proposition}

\begin{proof}
Injectivity and disjoint modes make the exchanged pairs disjoint.
At \(j=0\), central reports are zero, arm formulas agree, and all
peripheral formulas coincide. Hence unchanged reports are valid.
Mode selects the outgoing germ, permission decreases, tables remain
fixed, and locations become exactly \(\tau(x)\).

The decoder ignores returned implementation history but does not
discard its wires. Report words are not promoted to new exact
lengths.
\end{proof}

With no encoded locations, the event mode/counter action is
\begin{equation}
 f(0,k)=(1,k-1),\qquad f(1,k-1)=(0,k),
 \qquad 1\le k\le2^r-1,
 \label{eq:counter-permutation}
\end{equation}
with \((0,0)\), \((1,2^r-1)\) fixed. For the exchange, this action
is enabled only on valid \(j=0\) event data; other strings remain
fixed. The reverse action is a reversible completion, not another
forward geometric rule.

% 55
\begin{proposition}[Exact finite circuit realization]
\label{prop:circuit}
The permutations \(U_A,U_B\) have exact finite
NOT--CNOT--Toffoli realizations with clean work returned in \(\ket0\).
Code, location, and history wires are returned.
The internal matter action is the identity.
\end{proposition}

\begin{proof}
Every finite permutation is a product of transpositions.
For two \(M\)-bit strings choose a nonrepeating Gray path
\(v_0,\ldots,v_D\). The product
\[
 (v_0v_1)\cdots(v_{D-2}v_{D-1})(v_{D-1}v_D)
 (v_{D-2}v_{D-1})\cdots(v_0v_1)
\]
exchanges the endpoints and restores the intermediate strings.
For \(D=1\), use the single adjacent transposition.

An adjacent transposition is a NOT on the differing bit, controlled
on the specified pattern of all other bits. Surrounding NOTs provide
negative controls. For two or more controls, compute their conjunction
into clean work using Toffoli gates, flip the target, and uncompute.
Zero and one control use NOT and CNOT.
At most \(M\) work bits suffice for this existence construction.

Every gate consumes and returns its interface. Work is uncomputed;
transport history is deliberately retained. Tensoring with the
identity on internal matter completes the realization.
\end{proof}

Sufficient data-wire counts, excluding fixed identifiers and tables,
are
\begin{equation}
 M_B=26(b+4)+1+r+(d+2)+2n\ell,
 \qquad
 M_A=5(b+4)+1+r+2n\ell.
 \label{eq:event-storage}
\end{equation}
The generic synthesis uses at most \(2M_B\) or \(2M_A\) wires including
clean work, plus tables and active matter. These are existence,
not efficiency, bounds.

The \(n\)-dependent storage is separately reserved transport/history
storage, not a global-name-count guard. The implementation covers
the discrete event only, not continuous affine evolution, arbitrary
real clocks, or arbitrary configurations.

\subsection{Certificate and scope}

% 56
\begin{theorem}[One complete four-face exchange]
\label{thm:exchange}
In the fixed cone with \(\mu=\pi/2\), the capped slicing
\cref{eq:capped} has exactly one central four-face exchange on
\([-1,1]\), with:
\begin{enumerate}
\item spacelike time-ordered slices and transverse central edge laws;
\item explicit adapted affine charts and exact local words;
\item certified event germs and an exact \(s=0\) guard;
\item a compact collar matching one fixed exterior cellulation;
\item abstract transport using declared location labels;
\item spectator-blind control under separate storage reservation;
\item an exact finite decoder-correct event implementation on its
      declared code family.
\end{enumerate}
The resting particle has, on both sides,
\begin{equation}
 \mu=\pi/2,\qquad p=e_0,\qquad
 \chi(p,n)=0,\qquad J=(R(\pi/2),0).
 \label{eq:particle-observables}
\end{equation}
\end{theorem}

\begin{proof}
The geometric claims are
\cref{prop:R1,prop:R2,prop:R3,prop:R4,prop:R5,prop:R6,
prop:cap,prop:collarproducts,prop:R8,prop:alllengths}.
Control and transport are \cref{prop:Gcertificate};
decoding and realization are \cref{prop:decoder,prop:circuit}.
The particle word and resting normal are unchanged.
\end{proof}

The event uses the interface theorem subject to its assumptions;
it does not supply those assumptions. No \(\Enter\) fires at the
event. Physical patch diameter is not a computational block-diameter
certificate, and the channel retiming theorem does not move the event
past a record-dependent or geometry-dependent gate.

The central incidence is the type A exchange pattern
of~\cite[Section 3.1]{tHooft1993}. This is not the full transition
catalogue. The patch contains no particle or nontrivial spacetime
monodromy. Ambient identity words also do not imply that every
intrinsic slice angle sum is \(2\pi\).

\paragraph{A different collapsed quadrilateral.}
For comparison, let
\[
 A=(-1,0),\ B=(1,0),\ C=(0,1-t),\ D=(0,t-1).
\]
For \(t\ne1\), the boundary order \(ABCD\) has crossing segments
\(AB,CD\). Its convex hull has area \(2\abs{1-t}\), so the whole
patch collapses. The proposed replacement \(AB\) has length \(2\),
rather than being born from zero. With spacetime time \(T=t\),
the \(A,B\) trajectories are timelike and \(C,D\) trajectories null.
This is not the certified exchange.

\section{Scale, records, and residual instruments}
\label{sec:scale}

Evolution, scale change, label aggregation, and measurement are
distinct maps. This section concerns named finite-dimensional
channels, not nonlinear coupling.

\subsection{Effect pullback}

Let
\begin{equation}
 T=\mathcal C_{\ell\to L}\circ\Phi_\ell:
 L(\cH_\ell)\longrightarrow L(\cH_L)
 \label{eq:scale-channel}
\end{equation}
be a channel. For a fine POVM \(\{F_z\}\), coarse POVM \(\{E_w\}\),
and label map \(q:Z\to W\), put
\begin{equation}
 \Pi_w=\sum_{z:q(z)=w}F_z.
 \label{eq:aggregated-effects}
\end{equation}
Empty sums are allowed; \(\{\Pi_w\}\) is a POVM.
The compared laws are
\begin{equation}
 p_T(w\mid\rho)=\Tr(E_wT(\rho)),\qquad
 p_f(w\mid\rho)=\Tr(\Pi_w\rho).
 \label{eq:record-laws}
\end{equation}
A fine readout intended at another time must first be pulled back
through its evolution.

% 57
\begin{theorem}[Exact record compatibility]
\label{thm:pullback}
The laws in \cref{eq:record-laws} agree for every input state and
outcome if and only if
\begin{equation}
 T^*(E_w)=\Pi_w\qquad(w\in W).
 \label{eq:pullback}
\end{equation}
\end{theorem}

\begin{proof}
Their difference is
\(\Tr(\rho[T^*(E_w)-\Pi_w])\).
The bracket is Hermitian. Testing its eigenvector states proves
that zero expectation for every state is equivalent to its vanishing.
\end{proof}

% 58
\begin{corollary}[Marginalization]
\label{cor:marginalization}
For \(T=\Tr_r\) on \(\cH_c\otimes\cH_r\), and
\(\Pi_w=E_w\otimes I_r\), compatibility is exact.
\end{corollary}

\begin{proof}
The adjoint of partial trace is \(E\mapsto E\otimes I_r\).
\end{proof}

\subsection{Exact unassisted error}

Set
\begin{equation}
 D_w=T^*(E_w)-\Pi_w,\qquad \sum_wD_w=0,
 \label{eq:effect-error}
\end{equation}
and
\begin{equation}
 \delta_{\mathrm{rec}}
 =\sup_{\rho\in D(\cH_\ell)}
       \tv(p_T(\cdot\mid\rho),p_f(\cdot\mid\rho)).
 \label{eq:delta-definition}
\end{equation}
No ancillary reference output is included.

% 59
\begin{proposition}[Event operator-norm formula]
\label{prop:recorderror}
With \cref{eq:distance-conventions},
\begin{equation}
 \boxed{
 \delta_{\mathrm{rec}}
 =\max_{A\subseteq W}
       \left\|\sum_{w\in A}D_w\right\|_\infty
 \le\frac12\sum_w\norm{D_w}_\infty.}
 \label{eq:delta-exact}
\end{equation}
\end{proposition}

\begin{proof}
For real zero-sum \(d_w\),
\[
 \frac12\sum_w\abs{d_w}
 =\max_{A\subseteq W}\abs{\sum_{w\in A}d_w}.
\]
Use \(d_w=\Tr(\rho D_w)\), interchange the finite maximum with the
state supremum, and apply
\(\sup_\rho\abs{\Tr(\rho H)}=\norm H_\infty\) for Hermitian \(H\).
The upper bound follows termwise.
\end{proof}

This dimensionless probability error is not a scalar physical readout
budget and is not a diamond norm~\cite{CheungPsy02A}.

% 60
\begin{example}[Hadamard incompatibility]
\label{ex:hadamard}
For \(T(\rho)=H\rho H\), computational effects on both sides, and
identity aggregation,
\[
 D_0=(X-Z)/2,\qquad D_1=-D_0,\qquad
 \delta_{\mathrm{rec}}=1/\sqrt2.
\]
The state \(\ket0\bra0\) gives only \(1/2\).
\end{example}

\subsection{Transport and coherence diagnostics}

For a fine PVM \(\{P_z\}\) with
\(\Pi_w=\sum_{q(z)=w}P_z\):

% 61
\begin{proposition}[Diagnostic decomposition]
\label{prop:decomposition}
For every state,
\begin{equation}
 \Tr(\rho D_w)=a_w(\rho)+b_w(\rho),
 \label{eq:transport-coherence}
\end{equation}
where
\begin{align}
 a_w(\rho)&=\sum_z\left[
 \Tr(E_wT(P_z\rho P_z))
 -\one_{\{q(z)=w\}}\Tr(P_z\rho)\right],\notag\\
 b_w(\rho)&=\sum_{z\ne z'}\Tr(E_wT(P_z\rho P_{z'})).
 \label{eq:transport-coherence-terms}
\end{align}
Both sums are real, and
\begin{equation}
 \tv(p_T,p_f)
 \le\frac12\sum_w(\abs{a_w(\rho)}+\abs{b_w(\rho)}).
 \label{eq:transport-coherence-bound}
\end{equation}
\end{proposition}

\begin{proof}
Insert \(\rho=\sum_{z,z'}P_z\rho P_{z'}\).
Off-diagonal terms occur in conjugate pairs.
Apply the triangle inequality.
\end{proof}

The first term diagnoses sector transport and the second
coherence-sensitive contributions. Cancellation of an aggregate
does not force each of its summands to vanish.

\subsection{Residual instruments}

For the fine PVM, define
\begin{equation}
 \cF(\rho)=
 \sum_w\ket w\bra w_R\otimes
       T\left(\sum_{z:q(z)=w}P_z\rho P_z\right).
 \label{eq:fine-instrument}
\end{equation}
For a complete coarse instrument, each \(\cI_w\) is CP and
\(\sum_w\cI_w\) is trace preserving. Set
\begin{equation}
 \cG(\rho)=
 \sum_w\ket w\bra w_R\otimes\cI_w(T(\rho)),
 \qquad E_w=\cI_w^*(I).
 \label{eq:coarse-instrument}
\end{equation}
Both outputs are on \(R\otimes\cH_L\).

% 62
\begin{theorem}[Residual-state obstruction]
\label{thm:obstruction}
Exact record compatibility does not imply \(\cF=\cG\), even when
\(T=\id\).
\end{theorem}

\begin{proof}
Take one qubit, computational \(P_0,P_1\), one outcome \(W=\{*\}\),
and the coarse identity instrument. Then \(E_*=\Pi_*=I\).
For \(\rho=\ket+\bra+\),
\begin{equation}
 \cG(\rho)=\ket*\bra*_R\otimes\ket+\bra+,\qquad
 \cF(\rho)=\ket*\bra*_R\otimes I/2.
 \label{eq:obstruction-outputs}
\end{equation}
The residual difference is \(X/2\), with eigenvalues \(\pm1/2\), so
\begin{equation}
 \norm{\cG(\rho)-\cF(\rho)}_1=1.
 \label{eq:obstruction-norm}
\end{equation}
The record error is zero, while residual trace distance is \(1/2\).
\end{proof}

\begin{processremark}
The process-level comparisons recorded by Cheung in
Psy02-A, Psy02-B, and En01-B distinguish sequential instruments,
complete-record overlap, and residual approximation
\cite{CheungPsy02A,CheungPsy02B,CheungEn01B}.
Equal complete classical records for a declared intervention family
do not identify its hidden residual mechanism, even when every
instrument is complete. Equality for one family does not imply
equality after enlarging that family. Conversely, if matched
accessible states evolve by the same history-dependent channels
and full instruments, induction gives equal records.
The precise finite statement is proved next; no conformational
model or apparatus calibration is imported.
\end{processremark}

\begin{interfaceprop}[Complete-process equality and identification cut]
\label{ip:process}
Fix a finite protocol, including all settings, failure outcomes,
stopping decisions, and retained classical records.
Let the unnormalized accessible branch states satisfy
\[
 \sigma_{hw}=\mathcal K_{w|h}(\Phi_h(\sigma_h)),
 \qquad
 p(h)=\Tr\sigma_h,
\]
where \(\Phi_h\) is a channel and \(\{\mathcal K_{w|h}\}_w\)
a complete instrument. The declared accessible state is assumed
sufficient for this continuation.

Two models with the same initial accessible state and the same
\(\Phi_h,\mathcal K_{w|h}\) after every allowed history have the same
complete record law.

For any two complete laws \(P,Q\), a randomized test
\(0\le\varphi\le1\), with
\(\alpha=E_P\varphi\) and \(\beta=E_Q(1-\varphi)\), satisfies
\begin{equation}
 \alpha+\beta\ge1-\tv(P,Q),
 \qquad
 \inf_\varphi(\alpha+\beta)=1-\tv(P,Q).
 \label{eq:process-testing}
\end{equation}
If \(P=Q\), every test has \(\alpha+\beta=1\).
No sample size distinguishes an identical null--alternative pair
under the declared repeated-run law.
\end{interfaceprop}

\begin{proof}
Induct on unnormalized branch states. Complete instruments include
all outcomes and preserve total probability when summed.
Input-independent random setting selection is included in the
history or aligned by the same seed.

For the test,
\[
 \alpha+\beta=1+E_P\varphi-E_Q\varphi.
\]
The maximum of \(E_Q\varphi-E_P\varphi\) is total variation, attained
by the indicator of outcomes where \(Q>P\). Identical independent
repeated-run laws have identical product laws. More generally,
the same conclusion holds whenever the complete joint repeated-run
laws are equal.
\end{proof}

A sufficient accessible state need not be the carrier marginal
alone. Hidden memory can invalidate a purported carrier-only
interval-channel description.

For example, start \(S\) in \(\rho\) and a bath qubit in \(I/2\).
Two successive SWAPs have carrier channels: depolarizing after the
first and identity after the second. A second model stores a uniformly
random Pauli label \(a\) classically and applies the same Pauli twice.
It has the same two unintervened single-time channels.
Replace the carrier by \(\ket0\bra0\) between steps.
The SWAP model returns \(\rho\), whereas the Pauli-label model returns
\(I/2\). Thus agreement without that intervention does not extend to
the replacement protocol.

Likewise, after the outputs in \cref{eq:obstruction-outputs}, an
\(X\)-basis readout gives probability \(1\) versus \(1/2\) for \(+\).
The residual difference becomes a later record difference.

If approximations obey
\[
 \norm{\widehat{\cF}(\rho)-\cF(\rho)}_1\le\varepsilon_f,\qquad
 \norm{\widehat{\cG}(\rho)-\cG(\rho)}_1\le\varepsilon_g,
\]
then the same input gives
\begin{equation}
 \norm{\widehat{\cG}(\rho)-\widehat{\cF}(\rho)}_1
 \ge1-\varepsilon_f-\varepsilon_g.
 \label{eq:approximate-obstruction}
\end{equation}
Improved implementation does not remove incompatible ideal targets.

\subsection{Accessible output algebras}

For a unital residual algebra \(\cA_L\), define
\begin{equation}
 \cO_L=
 \left\{\sum_w\ket w\bra w_R\otimes A_w:A_w\in\cA_L\right\}.
 \label{eq:output-algebra}
\end{equation}

% 63
\begin{definition}[Accessible comparison]
\label{def:accessible}
Outputs agree operationally on \(\cO_L\) if all its expectations
agree. For channels with the same output interface,
\begin{equation}
 d_{\cO_L}(\cF,\cG)
 =\frac12\sup_\rho
 \sup_{\substack{A=A^\dagger\in\cO_L\\\norm A_\infty\le1}}
 \abs{\Tr(A[\cF(\rho)-\cG(\rho)])}.
 \label{eq:accessible-distance}
\end{equation}
\end{definition}

% 64
\begin{proposition}[Accessible-algebra criterion]
\label{prop:accessible}
Agreement on \(\cO_L\) for every input is equivalent to
\begin{equation}
 \cF^*(A)=\cG^*(A)\qquad(A\in\cO_L).
 \label{eq:accessible-pullback}
\end{equation}
Moreover,
\begin{equation}
 d_{\cO_L}(\cF,\cG)
 =\frac12
 \sup_{\substack{A=A^\dagger\in\cO_L\\\norm A_\infty\le1}}
 \norm{\cF^*(A)-\cG^*(A)}_\infty.
 \label{eq:accessible-norm}
\end{equation}
\end{proposition}

\begin{proof}
Self-adjoint expectations identify the Hermitian adjoint images.
Every algebra element is a complex linear combination of
self-adjoint elements. Interchange the two suprema and optimize
the Hermitian expectation spectrally.
\end{proof}

For \(\cA_L=\C I\), this is the record criterion and
\(d_{\cO_L}=\delta_{\mathrm{rec}}\).
For the full residual algebra, it compares complete instrument
outputs.

\begin{interfaceprop}[Closure of an observation boundary]
\label{ip:algebraclosure}
Let \(\Lambda:L(\cH_{\mathrm{in}})\to L(\cH_{\mathrm{out}})\)
be a channel and let \(\cA,\cB\) be unital \(^{*}\)-subalgebras.
Equality of input states on \(\cA\) implies equality of their
outputs on \(\cB\) for every pair of states if and only if
\begin{equation}
 \Lambda^*(\cB)\subseteq\cA.
 \label{eq:continuation-closure}
\end{equation}
For inputs restricted to a classical block-diagonal state space,
replace \(\Lambda^*(\cB)\) by
\(\mathcal P_{\mathrm{cl}}(\Lambda^*(\cB))\), where
\(\mathcal P_{\mathrm{cl}}\) is its block pinching and
\(\cA\) lies in that block algebra.
\end{interfaceprop}

\begin{proof}
Inclusion gives the implication by the adjoint identity.
For necessity, let \(H=H^\dagger\in\cB\).
Any Hermitian \(\Delta\) orthogonal to \(\cA\) is traceless because
\(I\in\cA\). For sufficiently small \(\epsilon>0\),
\(I/d\pm\epsilon\Delta\) are states agreeing on \(\cA\).
The hypothesis gives
\(\Tr(\Delta\Lambda^*(H))=0\).
Finite-dimensional Hilbert--Schmidt orthogonality places
\(\Lambda^*(H)\) in the self-adjoint part of \(\cA\).
Extend by complex linearity.

For classical inputs use only block-diagonal \(\Delta\); their
pairings depend exactly on the pinched adjoint.
\end{proof}

This criterion explains why a later coherence-sensitive continuation
must declare a larger boundary if the earlier interface retained
only populations~\cite{CheungVIIE}.

\paragraph{A restricted classical population boundary.}
Consider the specifically declared zero-Hamiltonian generator
\[
 \dot\rho=
 \sum_{i\ne j}\gamma_{ij}(t)
 \left(
  \ket i\bra j\,\rho\,\ket j\bra i
  -\frac12\{\ket j\bra j,\rho\}
 \right),
 \qquad \gamma_{ij}(t)\ge0.
\]
Directly,
\begin{equation}
 \dot p_i=\sum_{j\ne i}\gamma_{ij}p_j
       -\sum_{k\ne i}\gamma_{ki}p_i.
 \label{eq:classical-population}
\end{equation}
Diagonal input states remain diagonal. Instruments whose admitted
population updates are substochastic classical matrices, with
complete sums, then give exactly the same complete history law as
the corresponding classical model, by branch induction.
For this generator there is no coherence-to-population term between
interventions. Introducing a Hamiltonian or a
coherence-to-population intervention changes that statement.
This is the restricted comparison recorded in
Psy03-A~\cite{CheungPsy03A}, not a theorem about every
zero-Hamiltonian quantum model.
A classical geometric label or diagonal record does not certify
a quantum residual.

\paragraph{Certified observation-law allowances.}
If actual laws satisfy uniformly in \(\rho\)
\[
 \tv(\widehat p_T,p_T)\le e_T,\qquad
 \tv(\widehat p_f,p_f)\le e_f,
\]
the triangle inequality gives
\begin{equation}
 \sup_\rho\tv(\widehat p_T,\widehat p_f)
 \le\delta_{\mathrm{rec}}+e_T+e_f.
 \label{eq:record-allowance}
\end{equation}
These allowances must be certified; the exact pullback identity
does not provide them.

More generally, if \(\tv(P,Q)\le e\), every score \(0\le f\le1\)
satisfies \(\abs{E_Pf-E_Qf}\le e\). Indeed,
\(f=\int_0^1\one_{\{f>u\}}\dd u\).
Taking suprema over one fixed test family preserves this allowance.
It applies to accuracy when the \emph{joint labelled observation
law} is the compared law, as in the leakage interface
of~\cite{CheungPsy03D}.

\paragraph{A separate assisted channel distance.}
If channel comparison with a reference is needed, define separately
\begin{equation}
 d_\diamond(\Phi,\Psi)=\frac12\norm{\Phi-\Psi}_\diamond.
 \label{eq:half-diamond}
\end{equation}
Here the diamond norm includes reference-assisted optimization.
For fixed CPTP pre- and postprocessing,
\[
 d_\diamond(\Omega\circ\Phi\circ\Lambda,
             \Omega\circ\Psi\circ\Lambda)
 \le d_\diamond(\Phi,\Psi).
\]
This follows from the induced trace-norm definition and
\(\norm{\Omega}_\diamond=\norm{\Lambda}_\diamond=1\)
\cite{Watrous2018}. It uses the half-diamond convention compared in
Em05-A~\cite{CheungEm05A}, and does not replace
\cref{eq:delta-exact}.

\subsection{Sharp residual compatibility}

% 65
\begin{proposition}[Sharp instruments and a sufficient dephasing condition]
\label{prop:fullcompat}
Let the fine measurement be a PVM \(\{P_z\}\), and the coarse
measurement a PVM \(\{E_w\}\) with Lüders maps
\(\cI_w(X)=E_wXE_w\).
Assume \(T^*(E_w)=\Pi_w\) for every \(w\). Then
\begin{equation}
 E_wT(X)E_w=T(\Pi_wX\Pi_w).
 \label{eq:sharp-block-intertwining}
\end{equation}
The full instruments \(\cF,\cG\) agree if and only if
\begin{equation}
 T(P_zXP_{z'})=0
 \quad\text{for all \(X\), whenever }z\ne z',\ q(z)=q(z').
 \label{eq:intra-outcome-condition}
\end{equation}
In particular, for
\(\cD(X)=\sum_zP_zXP_z\), the additional condition
\begin{equation}
 T=T\circ\cD
 \label{eq:fullcompat-dephasing}
\end{equation}
is sufficient.
\end{proposition}

\begin{proof}
Choose Kraus operators \(K_a\) for \(T\).
For \(v\in\operatorname{ran}P_z\), pullback compatibility gives
\[
 \sum_a\norm{(I-E_{q(z)})K_av}^2
 =\Tr((I-E_{q(z)})T(\ket v\bra v))=0.
\]
Thus \(E_wK_aP_z=\one_{\{q(z)=w\}}K_aP_z\).
Summing the Kraus formula proves
\cref{eq:sharp-block-intertwining}.

Consequently each coarse block is
\[
 E_wT(X)E_w
 =\sum_{\substack{z,z'\\q(z)=q(z')=w}}T(P_zXP_{z'}).
\]
The fine block retains only its \(z=z'\) terms.
Condition~\eqref{eq:intra-outcome-condition} is sufficient.
If instruments agree for all states, linear spanning extends the
identity to every \(X\). Substitute a single off-diagonal block
\(X=P_zYP_{z'}\) with equal coarse label to obtain necessity.

Finally, \(T=T\circ\cD\) kills every fine off-diagonal block.
\end{proof}

The exact remaining certificate concerns intra-outcome coherence.
Global dephasing is stronger than necessary. Coarse effects alone
still do not select a coarse instrument.

\subsection{Capacity and a complete storage boundary}

For a fixed task and observation interface, let
\(\mathfrak I_K\subseteq\mathfrak I_{K'}\) when \(K\le K'\).
Define
\begin{equation}
 \varepsilon_K=\inf_{\mathcal J\in\mathfrak I_K}\Err(\mathcal J),
 \qquad \inf\varnothing=+\infty.
 \label{eq:optimized-error}
\end{equation}

% 66
\begin{proposition}[Optimized capacity monotonicity]
\label{prop:capacity}
Nested feasibility sets give
\(\varepsilon_{K'}\le\varepsilon_K\) for \(K'\ge K\).
They do not imply \(\varepsilon_K\to0\).
\end{proposition}

\begin{proof}
An infimum over a larger set cannot increase. All feasible members
may nevertheless retain a fixed positive error floor.
\end{proof}

\paragraph{Complete retained-state accounting.}
A model asserting at most \(K\) \emph{classical retained values}
must count the entire input-dependent state available to its
controller or decoder. Every additional readable record, current-input
register, timing signal, environment flag, geometry label, or history
must either pass through that state or be an explicitly declared
additional input. Independent shared randomness may be conditioned
upon, but may not depend on fresh inputs.
This is the complete-storage boundary described in the supplied
Psy04-A record~\cite{CheungPsy04A}.

A budget of \(K\) classical values is not the same as \(K\) wires:
\(m\) binary wires can encode \(2^m\) values. Neither convention is
implicitly imposed on the event implementation.
For spectator blindness, every controller-readable variable is
inside the observation boundary regardless of whether it is charged
to a separate budget.

\begin{interfaceprop}[Classical-register carrier memory]
\label{ip:classicalmemory}
A Markovian update on an enlarged classical--quantum state can have
carrier-only history dependence after a carrier replacement.
A complete carrier reset need not erase a persistent classical label.
\end{interfaceprop}

\begin{proof}
Let the carrier be a qubit and \(K\) a classical bit.
An earlier allowed setting \(h\in\{0,1\}\) writes \(K=h\).
Replace the carrier by \(\ket0\bra0\), leaving \(K\) untouched.
Finally apply \(X^K\) and measure the carrier in the computational
basis. The outcome equals \(h\).

Immediately after replacement, both carrier states are
\(\ket0\bra0\), but the joint states are
\[
 \ket0\bra0_S\otimes\ket h\bra h_K.
\]
Each enlarged update is a specified Markov channel on \(S\otimes K\).
The later carrier law depends on history through \(K\) despite the
identical causal-break carrier state.

For the reset channel
\(\mathcal R(X)=\ket0\bra0\Tr X\), carrier trace distance becomes
zero in each sector. The label remains perfectly distinguishable.
\end{proof}

This is an operational-memory witness under a carrier-only experiment,
not a quantum-memory-resource certificate
\cite{CheungPsy03B,CheungPsy03C}.
Destructive \(\Enter\) removes its measured factor, but does not
automatically erase external geometry, its record, or returned
transport history.

Feasibility, approximation of a fixed target, and compatibility of
ideal targets remain three separate questions. Additional capacity
can help the first two; it does not alter the third by definition.

\section{Conditional approximation and verification interfaces}
\label{sec:approx}

The exact identities above do not imply quantitative continuity.
This section supplies conditional, locally proved certificates.
They follow the accounting style of the supplied input-stability,
residual, and independent-run records
\cite{CheungEm06B,CheungEn01B,CheungPsy03A,CheungPsy03D},
without importing their physical models or constants.

\subsection{Topology, guards, and a finite stability allowance}

Choose a metric \(d_Q\) on the compared geometric descriptions within
one fixed admissible branch or stratum. Give state functionals the
dual norm
\begin{equation}
 \norm{\omega_\rho-\omega_\sigma}_{\cA}
 =
 \sup_{\substack{A=A^\dagger\in\cA\\\norm A_\infty\le1}}
       \abs{\Tr((\rho-\sigma)A)}
 \le2\td(\rho,\sigma).
 \label{eq:functional-topology}
\end{equation}
Specify the controller topology separately. In the following
certificate, its finite command choices and interfaces are
\emph{aligned}. This alignment requires an exact agreement argument,
a robust guard margin, or a separate certified branch-mismatch law.
It is not inferred from a small state norm.

An equality guard such as \(s=0\) is generally discontinuous under
arbitrary clock perturbations. The event example preserves its exact
clock; noisy event detection is not included.

\begin{interfaceprop}[Conditional finite-run stability]
\label{ip:stability}
Suppose two aligned executions have original accessible state
distance \(e_k\), geometric distance \(d_k\), and the same current
interfaces. Suppose certified bounds at each step give
\begin{equation}
 \begin{aligned}
 e_{k+1}&\le e_k+L^m_kd_k+\eta^m_k,\\
 d_{k+1}&\le L^g_kd_k+2L^a_ke_k+\eta^g_k,
 \end{aligned}
 \label{eq:stability-recursion}
\end{equation}
with nonnegative constants. Let
\[
 E_k=e_k+d_k,\qquad
 L_k=\max\{1+2L^a_k,L^m_k+L^g_k\},\qquad
 \eta_k=\eta^m_k+\eta^g_k.
\]
Then
\begin{equation}
 E_T\le
 \left(\prod_{k=0}^{T-1}L_k\right)E_0
 +\sum_{j=0}^{T-1}
       \left(\prod_{k=j+1}^{T-1}L_k\right)\eta_j.
 \label{eq:input-stability-allowance}
\end{equation}
A fixed final readout has record discrepancy at most \(e_T\).
\end{interfaceprop}

\begin{proof}
Adding the two inequalities gives \(E_{k+1}\le L_kE_k+\eta_k\).
Iteration proves the display, with empty products equal to \(1\).
Fixed readout contracts trace distance into total variation.
\end{proof}

The hypotheses have concrete meanings. For a matter step they follow
from trace-distance contraction and a certified bound
\[
 \sup_\rho\td(\Psi_q(\rho),\widehat\Psi_{\widehat q}(\rho))
 \le L^m_kd_Q(q,\widehat q)+\eta^m_k.
\]
For a coupling step they follow from a declared Lipschitz bound in
\(d_Q\) and the functional norm of
\cref{eq:functional-topology}. For a geometric step, accessible
matter is unchanged.
None of these constants or the guard alignment follows solely from
\cref{thm:spectators,thm:deferred}.

\subsection{Integrated residual certificates}

\begin{interfaceprop}[Unnormalized residual-state allowance]
\label{ip:residual}
Let \(\mathcal U(t,s)\) be a finite-dimensional linear propagator
contractive in trace norm on Hermitian operators.
Suppose
\[
 \dot\sigma(t)=\mathcal L_t\sigma(t),\qquad
 \dot{\widehat\sigma}(t)=\mathcal L_t\widehat\sigma(t)+r(t),
\]
where \(r(t)\) is integrable and Hermitian and the usual
variation-of-constants identity holds. Then
\begin{equation}
 \norm{\widehat\sigma(t)-\sigma(t)}_1
 \le\norm{\widehat\sigma(0)-\sigma(0)}_1
       +\int_0^t\norm{r(u)}_1\dd u.
 \label{eq:integrated-residual}
\end{equation}
This applies to unnormalized instrument blocks when their declared
propagators are CP and trace nonincreasing.
\end{interfaceprop}

\begin{proof}
The difference is
\[
 \mathcal U(t,0)(\widehat\sigma(0)-\sigma(0))
 +\int_0^t\mathcal U(t,u)r(u)\dd u.
\]
Contractivity and the triangle inequality give the result.
For a CP trace-nonincreasing map and Hermitian
\(H=H_+-H_-\), positivity gives
\[
 \norm{\mathcal U(H)}_1
 \le\Tr\mathcal U(H_+)+\Tr\mathcal U(H_-)
 \le\norm H_1.
\]
\end{proof}

This is the residual accounting form compared with
En01-B~\cite{CheungEn01B}. It supplies a quantitative certificate only
after the target dynamics and residual \(r\) are supplied.
It does not convert record equality into residual equality.

Normalization of a rare branch requires a probability lower bound.
For positive blocks of traces \(p,\widehat p>0\) with
\(\norm{\widehat\sigma-\sigma}_1\le\epsilon\),
\[
 \left\|\frac{\widehat\sigma}{\widehat p}
             -\frac{\sigma}{p}\right\|_1
 \le\frac{2\epsilon}{p}.
\]
Thus small unconditional block error alone does not uniformly
control every normalized conditional state.

\subsection{Independent-run sampling}

\begin{interfaceprop}[Attempted-run scalar certificate]
\label{ip:scalar-sampling}
Let \(H_1,\ldots,H_N\) be independent, identically distributed
complete attempted-run histories from one fixed protocol.
For a prespecified score \(f(H)\in[0,1]\), write
\(\widehat\mu=N^{-1}\sum_i f(H_i)\).
For \(0<\alpha<1\), with probability at least \(1-\alpha\),
\begin{equation}
 \abs{\widehat\mu-Ef}
 \le\sqrt{\frac{\log(2/\alpha)}{2N}}.
 \label{eq:scalar-radius}
\end{equation}
\end{interfaceprop}

\begin{proof}
Hoeffding's inequality gives
\(\Pr(\abs{\widehat\mu-Ef}>u)\le2e^{-2Nu^2}\)
\cite{Hoeffding1963}. Substitute the displayed radius.
\end{proof}

A run, or a fresh sequence, is the independent unit
\cite{CheungPsy03A,CheungPsy03D}.
Dependence between observations within a run does not increase \(N\).
Failure and aborted outcomes must be included in the attempted-run
law and assigned a prespecified score. Conditional successful-run
sampling estimates a different law unless its selection correction
is separately certified.

\begin{interfaceprop}[Finite complete-record certificate]
\label{ip:record-sampling}
Let \(P_0,P_1\) be complete laws on one finite alphabet
\(\Omega\), with \(m=\abs{\Omega}\), and let
\(\widehat P_j\) be empirical laws from \(N_j\) independent runs
of each protocol. Put
\[
 r_j=\sqrt{\frac{\log(4m/\alpha)}{2N_j}},
 \qquad
 \widehat\Delta=\tv(\widehat P_0,\widehat P_1).
\]
With probability at least \(1-\alpha\),
\begin{equation}
 \max\left\{0,\widehat\Delta-\frac m2(r_0+r_1)\right\}
 \le\tv(P_0,P_1)
 \le
 \min\left\{1,\widehat\Delta+\frac m2(r_0+r_1)\right\}.
 \label{eq:complete-record-radius}
\end{equation}
\end{interfaceprop}

\begin{proof}
Apply the scalar bound to every outcome indicator with the displayed
coordinate radius. A union bound over the \(2m\) coordinates gives
simultaneous coordinate errors at most \(r_j\) with failure
probability at most \(\alpha\).
Then
\(\tv(P_j,\widehat P_j)\le mr_j/2\).
The two triangle inequalities prove the interval.
\end{proof}

This certificate is for the specified inputs and complete protocols.
It is not a universal all-input verification of
\(T^*(E_w)=\Pi_w\), and not a mechanism-identification theorem.
A finite input bank can be certified by an additional union bound;
coverage of all states requires a separate argument.
Identical complete laws remain indistinguishable, as in
\cref{ip:process} and the supplied sampling comparison
\cite{CheungPsy02B}.

\section{Limitations and open interfaces}
\label{sec:limitations}

\subsection{Prescribed substrate and physical causal structure}

Scheduled containment needs a computational metric, channel supports,
and a complete network. Periodic graph propagation can be anisotropic
\cite{Fritz2013}. Lorentz-equivariant association of a finite-valency
graph to a Minkowski sprinkling has a separate obstruction
\cite{BombelliHensonSorkin2009}. Randomizing partitions is not a proof
of physical causal dominance.

Scalar finite-propagation source records such as
Em06-B~\cite{CheungEm06B} motivate accounting for compact causal pasts
on finite time slabs. They do not derive a metric from this interface
or transfer a scalar field equation.

Preferred-frame radiative effects require independent analysis
\cite{Collins2004}. The schedule theorem alone is not a Lorentz
invariance certificate.

\subsection{Geometry and the single exchange}

The finite implementation certifies a discrete event in a fixed family.
All moving-patch transitions are pure gauge in one flat development.
The example does not test support containing a particle or nontrivial
monodromy. It supplies neither a complete transition catalogue nor
a canonical constraint algebra for a full polygon implementation.

The compact collar is essential. An unbounded maximum graph without
boundary matching would not establish a move attached to the same
fixed conical exterior.

\subsection{Nonlinear and classical--quantum evolution}

A state-functional coupling needs independent physical consistency
tests. A different linear hybrid model may use
\[
 \sigma=\sum_q\ket q\bra q\otimes\rho_q,
\]
and
\begin{equation}
 \mathfrak F(\sigma)
 =\sum_{q,q'}\ket{q'}\bra{q'}\otimes\Psi_{q'|q}(\rho_q),
 \label{eq:cq-evolution}
\end{equation}
where \(\Psi_{q'|q}\) are CP and
\(\sum_{q'}\Psi_{q'|q}\) is trace preserving for every \(q\),
with admissibility on every permitted transition.
This is not an automatic rewriting of deterministic nonlinear
coupling.

A persistent external classical register is not identified with
quantum environmental memory. The classical witness in
\cref{ip:classicalmemory} already suffices for carrier-only
history dependence.

\subsection{Readout, approximation, and inference}

The deferred theorem excludes intermediate access to \(R,S,A\).
Gravitating records or record-dependent geometry require a larger
instrument and controller interface.

Approximation needs a topology, stability constants, and branch
control. Sampling needs a complete attempted-run law and independent
units. Neither establishes the observation boundary from an empirical
score alone. Quantum residual certification requires residual
observables or a justified instrument model, not merely population
agreement.

\subsection{Continuum and separate programmes}

No continuum gravitational dynamics, weak-field attraction, curvature
limit, or common-metric test is established.
Quantum superpositions of geometry require joint quantum-geometric
semantics beyond external metadata.

The conical witness and pure-gauge exchange neither open a separate
interacting quantum-product construction nor close a spacetime-
emergence problem. In the supplied programme terminology,
O.1 remains \texttt{NOT\_CLOSED}, and XV-B is not opened.
This document reports no execution of a TeX compiler. The locally
proved finite event-circuit existence theorem is a mathematical
claim, not a compiler-execution report or a compilation of the
separate field-theoretic programme.

% 67
\begin{openproblem}[Beyond the pure-gauge exchange]
\label{op:transitions}
Construct a certified transition containing a particle or nontrivial
monodromy, or another transition type. Supply complete affected
labels, boundary matching, ordered affine words, transport, control,
and a decoder equation.
For approximate event detection, distinguish off-event geometric
error from event-time and event-resolution error.
\end{openproblem}

% 68
\begin{openproblem}[Controlled scale approximation]
\label{op:approximation}
For a specified accessible algebra and resource model, construct
nested implementation families with an explicit approximation rate.
Keep ideal compatibility separate from implementation error.
Increasing workspace alone is not a convergence proof.
\end{openproblem}

% 69
\begin{openproblem}[Physical schedule dominance]
\label{op:dominance}
For a moving geometric model and computational substrate, prove
directional inclusion of physical dependency regions in scheduled
regions, including encoding, decoding, control, and transport.
A scalar speed comparison is insufficient.
\end{openproblem}

\section{Conclusion}

The paper establishes an observation interface, not a gravitational
derivation.

Destructive \(\Enter\), coherent recording, and nondestructive
instruments have different outputs. Keeping those outputs distinct
gives a restricted deferred-readout identity on a common accessible
interface.

Spectator invariance covers arbitrary extensions with the same
accessible reduction. Its boundary includes geometry, coupling,
control, guards, capacities, locations, and readable histories.
Coupling-algebra blindness alone is insufficient.

Scheduled ancestors upper-bound prescribed channel influence and
give a reference-complete causal cut. They are not automatically
physical light cones, and their channel theorems do not extend
silently to nonlinear coupling.

Record compatibility is the pullback
\(T^*(E_w)=\Pi_w\). Its exact unassisted error is an event operator
norm. Residual compatibility is a separate instrument certificate;
complete records identify only the declared operational family.
A classical register can retain carrier-only memory without a
quantum-memory-resource claim.

The geometric examples provide external conical data, a gauge flip,
and one complete compactly attached four-face exchange in a fixed
spacetime. Its exact event implementation retains noninjective
transport history rather than erasing it.

Names are not mass, capacity is not curvature, and destructive
measurement is not coarse-graining.

\appendix
\section{Documentary source ledger}
\label{app:sources}

The companion identifiers below are source records, not formal
premises of the proofs. Full passages were supplied for I, VII-E,
and selected VII-J statements. Other entries were supplied as
statement summaries or revision recommendations. They are cited
at that level; no missing full text or publication metadata is
reconstructed.

\begin{longtable}{@{}p{.22\textwidth}p{.34\textwidth}p{.37\textwidth}@{}}
\toprule
Source record & Interface comparison & Local replacement or boundary\\
\midrule
\endfirsthead
\toprule
Source record & Interface comparison & Local replacement or boundary\\
\midrule
\endhead
\bottomrule
\endfoot
I; Enter article &
Destructive measurement and surviving interfaces &
\cref{def:enter,def:recording,def:nondestructive};
Born semantics assumed, not rederived.\\
VII-E &
Observation boundary, records, residuals, continuation &
\cref{thm:spectators,thm:pullback,prop:accessible,
ip:algebraclosure}; all proofs local.\\
VII-J &
Scheduled ancestors and no-signalling factorization &
\cref{ip:nosignal,ip:networkcut}; no physical cone
or speed constant imported.\\
Psy02-A &
Sequential instruments and probability error &
\cref{thm:obstruction,ip:process};
effects alone do not specify updates.\\
Psy02-B &
Complete-process equality, overlap, and sampling &
\cref{ip:process,ip:record-sampling};
no conformational model imported.\\
Psy03-A &
Classical population boundary and evaluation &
\cref{eq:classical-population,ip:scalar-sampling};
generator and independence stated locally.\\
Psy03-B; Psy03-C &
Classical-register memory and persistent-label obstruction &
\cref{ip:classicalmemory}; no quantum-memory
resource inference.\\
Psy03-D &
Observation obstruction, leakage, sequence concentration &
\cref{eq:record-allowance,ip:scalar-sampling};
changing the carrier does not add an observation channel.\\
Psy04-A &
Complete retained-state capacity boundary &
Source-summary comparison only; no unavailable
capacity theorem imported.\\
Em05-A &
Half-diamond normalization and spectator conventions &
\cref{eq:half-diamond}; arbitrary extensions here use
\cref{lem:trace}, not a pure-spectator shortcut.\\
Em06-B &
Declared-family stability and causal accounting &
\cref{ip:stability}; no scalar coefficient,
field equation, or metric transferred.\\
En01-B &
Unnormalized residual accounting &
\cref{ip:residual}; no calibration or apparatus
model transferred.\\
\end{longtable}

\begin{thebibliography}{99}

\bibitem{Cheung2026Enter}
N.~Cheung,
The Enter Calculus: A Linear Quantum Lambda Calculus with an
Operational Characterization of Measurement,
\emph{Frontiers in Physics}, Quantum Engineering and Technology,
accepted 28 September 2026.
Publisher lists volume 14 (2026); final formatted version pending
on the accepted-article page checked 10 October 2026.
DOI:
\href{https://doi.org/10.3389/fphy.2026.1954943}
{\nolinkurl{10.3389/fphy.2026.1954943}}.

\bibitem{CheungI}
N.~Cheung,
\emph{Manuscript I}, version 1,
Enter Calculus Companion, undated manuscript.
Supplied passage: ``Problem: a fixed language and a variable Enter.''
Documentary comparison for destructive measurement.
Companion registry: \url{https://enter.grok.me}.

\bibitem{CheungVIIE}
N.~Cheung,
\emph{Manuscript VII-E}, version 1,
Enter Calculus Companion, undated manuscript.
Supplied passage: ``The closed observation problem: results and
dependencies.'' Documentary comparison; no external proof is used.

\bibitem{CheungVIIJ}
N.~Cheung,
\emph{Manuscript VII-J}, version 1,
Enter Calculus Companion, undated manuscript.
Documentary source record for scheduled reachability,
no-signalling, and fixed-cone gate certificates.
The schedule and no-signalling labels are supplied in the revision
summary; selected fixed-cone passages were also supplied.
No full-manuscript verification is claimed.

\bibitem{CheungPsy02A}
N.~Cheung,
\emph{Manuscript Psy02-A},
Enter Calculus Companion, undated manuscript.
Cited from supplied statement summaries identifying
\texttt{prop:instrument}, \texttt{thm:readout}, and
\texttt{prop:noise}. Documentary source record, not a
verified journal publication.

\bibitem{CheungPsy02B}
N.~Cheung,
\emph{Manuscript Psy02-B},
Enter Calculus Companion, undated manuscript.
Cited from supplied summaries identifying
\texttt{thm:process}, \texttt{thm:overlap}, and
\texttt{thm:sampling}. Complete-process comparison only.

\bibitem{CheungPsy03A}
N.~Cheung,
\emph{Manuscript Psy03-A},
Enter Calculus Companion, undated manuscript.
Cited from supplied summaries identifying
\texttt{thm:classicalboundary} and \texttt{thm:evaluation}.
No network or biological model is imported.

\bibitem{CheungPsy03B}
N.~Cheung,
\emph{Manuscript Psy03-B},
Enter Calculus Companion, undated manuscript.
Cited from supplied summaries identifying
\texttt{def:state} and \texttt{thm:operationalmemory}.
Classical-register process comparison only.

\bibitem{CheungPsy03C}
N.~Cheung,
\emph{Manuscript Psy03-C},
Enter Calculus Companion, undated manuscript.
Cited from the supplied summary of \texttt{prop:register}.
Persistent-register comparison only.

\bibitem{CheungPsy03D}
N.~Cheung,
\emph{Manuscript Psy03-D},
Enter Calculus Companion, undated manuscript.
Cited from supplied summaries identifying
\texttt{prop:leakage}, \texttt{cor:qobstruction}, and
\texttt{thm:sequencehoeffding}.
Observation and independent-sequence comparison only.

\bibitem{CheungPsy04A}
N.~Cheung,
\emph{Psy04-A source record},
undated supplied manuscript summary.
Delayed-access storage boundary, identified as
\texttt{ass:boundary} in the revision materials.
A complete manuscript and independently verified publication
record were not available; no theorem is imported from it.

\bibitem{CheungEm05A}
N.~Cheung,
\emph{Manuscript Em05-A},
Enter Calculus Companion, undated manuscript.
Supplied source-summary comparison for
\texttt{thm:channels}, fixed-spectator conventions, and
half-diamond distance normalization.
No extraction model is imported.

\bibitem{CheungEm06B}
N.~Cheung,
\emph{Manuscript Em06-B},
Enter Calculus Companion, undated manuscript.
Supplied source-summary comparison for finite propagation,
\texttt{thm:input-stability}, and \texttt{cor:combined}.
No scalar equation or coefficient is imported.

\bibitem{CheungEn01B}
N.~Cheung,
\emph{Manuscript En01-B},
Enter Calculus Companion, undated manuscript.
Cited from the supplied summary of \texttt{prop:residual}.
Residual-accounting comparison only; no apparatus model is imported.

\bibitem{Watrous2018}
J.~Watrous,
\emph{The Theory of Quantum Information},
Cambridge University Press, 2018.

\bibitem{GurevichBlass2022}
Y.~Gurevich and A.~Blass,
Quantum circuits with classical channels and the principle of
deferred measurements,
\emph{Theoretical Computer Science} \textbf{920} (2022), 21--32.
arXiv:2107.08324.

\bibitem{DeserJackiwHooft1984}
S.~Deser, R.~Jackiw, and G.~'t~Hooft,
Three-dimensional Einstein gravity: dynamics of flat space,
\emph{Annals of Physics} \textbf{152} (1984), 220--235.

\bibitem{tHooft1992}
G.~'t~Hooft,
Causality in (2+1)-dimensional gravity,
\emph{Classical and Quantum Gravity} \textbf{9} (1992), 1335--1348.

\bibitem{tHooft1993}
G.~'t~Hooft,
The evolution of gravitating point particles in 2+1 dimensions,
\emph{Classical and Quantum Gravity} \textbf{10} (1993), 1023--1038.

\bibitem{Kadar2005}
Z.~K\'ad\'ar,
Polygon model from first order gravity,
\emph{Classical and Quantum Gravity} \textbf{22} (2005), 809--824.
arXiv:gr-qc/0410012.

\bibitem{Fritz2013}
T.~Fritz,
Velocity polytopes of periodic graphs and a no-go theorem for digital
physics,
\emph{Discrete Mathematics} \textbf{313} (2013), 1289--1301.
arXiv:1109.1963.

\bibitem{BombelliHensonSorkin2009}
L.~Bombelli, J.~Henson, and R.~D.~Sorkin,
Discreteness without symmetry breaking: a theorem,
\emph{Modern Physics Letters A} \textbf{24} (2009), 2579--2587.
arXiv:gr-qc/0605006.

\bibitem{Collins2004}
J.~Collins, A.~Perez, D.~Sudarsky, L.~Urrutia, and H.~Vucetich,
Lorentz invariance and quantum gravity: an additional fine-tuning
problem?,
\emph{Physical Review Letters} \textbf{93} (2004), 191301.
arXiv:gr-qc/0403053.

\bibitem{Hoeffding1963}
W.~Hoeffding,
Probability inequalities for sums of bounded random variables,
\emph{Journal of the American Statistical Association}
\textbf{58} (1963), 13--30.

\end{thebibliography}

\end{document}