Enter as an interface discipline

Cheung's Enter calculus uses a strictly linear treatment of quantum names and destructive computational-basis readout. Its operational characterization of measurement is class-relative; it is not a characterization of every possible continuum field instrument CheungEnter,CheungI.

The accompanying philosophy essay distinguishes the classical record returned by destructive readout from a quantum-return recovery map CheungPhilosophy. The relevant questions are:

Here the supplied objects are finitely many classical evaluations and their declared encodings. The output contains a classical code and the actual unmeasured finite residual.

In particular,

The complete finite instrument is proved in Section sec:instrument; no general measurement uniqueness theorem is needed for that matrix calculation.