V.P07 — CMB multipoles as boundary characters

The CMB multipole coefficient a_{ell,m} is the (ell,m)-component of the boundary-character expansion of Sigma_CMB: a_{ell,m} = _{H_partial}, with the acoustic peaks controlled by kappa(omega)/kappa(B), damping tail by kappa(B;1), and ISW by kappa(D;1) = 1 - iota_tau.