The separate characteristic-map programme remains open

The supplied material also describes a distinct analytic programme for a retained six-branch response. That programme is not solved by a finite channel analogy. We record its boundary without converting an unconstructed map into a nonexistence theorem.

Cheung's XIV-I supplies an internal amplitude construction at I2, while its joint characteristic map remains unresolved at I3. XIV-J supplies reconstruction constraints and a supported-sector reference, while the full map remains unresolved at J2 CheungXIVI,CheungXIVJ.