Definition: Compared extrapolation at a cut

At a declared cut, supply:

1. a physical accessible channel and a proxy accessible channel on the same code, after justified access-preserving identifications;

2. a common accessible comparison dimension $L$, with $d_{\diamond }({{\mathcal{N}}_{\mathrm{phys}}}^U,{{\mathcal{N}}_{\mathrm{proxy}}}^U)\le \eta$;

3. a physical detector channel compared with the proxy basis readout, with channel allowance $\nu$, and common record dimension $K$;

4. a distribution $\mu$ of proxy unitaries with TV allowance $\tau$, if an exact Haar-mean comparison is desired;

5. real target capacities $A,B$ and integer proxy dimensions $r,b$ with

   $$|{\log }_{2}r-A|\le e_R,|{\log }_{2}b-B|\le e_B.$$

The physical and proxy families must be coupled on these interfaces. If a temporal claim is made, the cuts must belong to compatible complete histories.