Finite probes and normalization freedom

If a finite probe map $P$ satisfies $P(B+Lc)=0$, the full identity follows only with independently proved coverage or injectivity on the allowed residual space. Otherwise a nonzero element of $\ker P$ is invisible.

Pure-trace probes in particular miss the smooth compact metric-slot kernel

This blind sector does not make a completely specified causal Green operator nonunique. It prevents selected contractions from certifying an unrestricted kernel CheungXVIIIA.