Enter and its spacetime interface

In Cheung's Enter calculus, runtime quantum names are access rights to tensor factors. Destructive computational-basis readout consumes the measured names and returns classical records. Unmeasured factors can remain available CheungEnter,CheungI. The characterization of the Born strategy in Manuscript I concerns its explicitly specified class and five requirements. We use a specified Born instrument and prove its channel formula; we do not rederive that characterization or extend it to quantum fields.

The accompanying philosophy distinguishes:

An output type does not determine the fate of all physical degrees of freedom used by an apparatus, and a channel does not specify a thermal machine CheungPhilosophy.

I-B supplies a finite operational interface on a prescribed conical spacetime CheungIB. A finite clock can be calibrated to its time coordinate, destructively read, and used for causal control. The geometric time axis, defect worldsheet, and future cone remain after that clock is consumed.