Question, contribution, and source interfaces

Psy04-A specifies a delayed random-access experiment with a complete storage boundary CheungPsy04A. The present manuscript asks how that boundary is represented as a cut in a complete causal process.

The established benchmark is unchanged: two uniform bits encoded in two classical states have optimal average late-query success $3/4$, whereas a qubit attains $1/2+1/(2\sqrt{2})$ AmbainisRAC. We prove these facts again for the exact class used here.

The new assembly consists of:

1. a complete finite network and scheduled-support theorem;

2. a decoder-relevant storage cut and its state assumptions;

3. explicit sequential Enter-compatible operations;

4. separation of retained memory from ancillary peak cost;

5. complete-record, robustness, and statistical interfaces;

6. a distinct null for an already quantum carrier with classical environmental feedback.

Finite quantum networks and memory-channel descriptions are established frameworks ChiribellaNetworks. The scheduled-support proof below is an elementary finite-channel specialization, not a new general theory of quantum causality.