Assumption: Extension class

The main ledger concerns

where $B_{\perp }$ is a self-adjoint extension of the transverse cone Laplacian in ${L^2}_{\beta }({C_{\alpha }}^{\circ },\alpha r\mathrm{d}r\mathrm{d}\phi )$. It is complex linear. Rotation invariance is imposed for the diagonal subledger but not for the full finite-dimensional boundary relation.

General $z$-dependent, longitudinal-momentum-dependent, and non-product extensions are outside this class.