Abstract

We formulate a finite admissibility interface for polygonal slices of a declared $2+1$-dimensional spinless conical spacetime. Geometric realization is checked before affine matching. The matching packet separates vertex and overlap equations, particle data, topologically marked holonomy words, collar agreement, and pointwise worldline fixation.

In a fixed developed presentation, incompatible proposed values of a prescribed transition cannot both be certified. A deterministic controller that factors through a named surviving observable algebra gives equal certified geometric outputs on equal accessible inputs, provided its complete control and resource specification is spectator blind. We prove the corresponding spectator-extension and restricted deferred-readout statements locally. An instrument-level obstruction shows why equal classical record laws do not determine residual source functionals.

For the fixed cone of deficit $\pi /2$, we give an explicit uniformly spacelike, embedded, acausal graph family with exactly one incidence event: the particle link changes from three faces to six. Exact vertices, lengths, areas, adapted affine charts, primitive winding, and full affine peripheral products furnish the certificate on both one-sided germs. The persistent particle signature is preserved, although the realization-dependent matching tables change. The intrinsic particle angle defects are computed separately and are not identified with the spacetime deficit.

Two incomplete updates fail different obligations. A changed deficit with a stale spatial rotation fails seam matching while still fixing the stationary worldline. A time-shifted rotation fails pointwise worldline fixation. The results establish an admissibility layer, not a sourced backreaction law, canonical polygon evolution, quantum recovery mechanism, or spacetime emergence theorem.