Choi and complementary-channel comparisons

A specified decoder can instead be certified by its normalized logical Choi error $r$, giving allowance $dr+b$. CPTP feasibility must be validated, including positivity and trace preservation on the entire finite input space. An optimization objective alone is not such a certificate.

Finite-channel certificates concern response and recovery. They do not certify magic unless a separate fixed-frame resource calculation is supplied.