Boundary Operator, Form Comparison, and Commutator Identities for Static Optical Metrics

We give the exact boundary-coordinate expression of the optical wave operator, prove a tangential-frequency-uniform form comparison with a frozen model, and establish exact Rellich-type commutator identities. We delimit why these identities alone do not yield universal absence of eigenvalues, and we state three open problems. The record contains the English version (main file), a faithful Portuguese version, and the supplementary archive (TeX, verification code, Lean/AXLE). Paper 3 of 3 on the spectrum of static optical metrics.