Quantum and classical interfaces

For the finite fragment, use types

with observable algebras

A hybrid state is block diagonal on its classical factors. A bit is not an unrestricted qubit under another name.

The primitives are pure allocation, specified unitary constants, destructive computational readout, and classical discard:

Return commands designate the retained interface; they are not additional dynamics.

Every live quantum wire is returned or explicitly consumed. It is never duplicated. Classical control acts separately on classical blocks. Only finite acyclic instruction trees are considered.

The fragment is defined here directly. The supplied Landmark I characterization concerns Born probabilities and positive-branch destructive residual rays within its own declared strategy class CheungI (thm:main). That full characterization is not reconstructed or imported. Likewise, the En03-A interface and scheduled-locality material is documentary CheungEn03A.