2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/217360We study the insertion and value of metric observables in the (discrete) path integral formulation of the Ponzano-Regge spinfoam model for 3d quantum gravity. In particular, we discuss the length spectrum and the relation between insertion of such B-observables and gauge fixing in the path integral.17 pagesGeneral Relativity and Quantum Cosmologytext