[Maro]

Classically, isn't the reverse program just (?):

X = 5

X = 4

I feel like 2 things are being mixed. In QM/QC, the operators must be unitary, which roughly means they "rotate" states and their inverse "rotation" exists, so (in principle) the reverse operation can be performed; so (in principle), we can construct the reverse operations, execute them, and kinda reverse the time evolution. But it doesn't mean that the quantum state (at time t) of the system encodes the time history (t'<t) of the state.

[whimsicalism]

> But it doesn't mean that the quantum state (at time t) of the system encodes the time history (t'<t) of the state.

it does if you take an everettian perspective on QM, the universal wavefunction at time T can always be unwound to time T'.

[currenciessfe]

I should have been more specific, the 4 and 5 values are dynamic runtime values, not constants known ahead of time.