2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/152736A refined expression for the Faddeev-Popov determinant is derived for gauge theories quantised around a reducible classical solution. We apply this result to Chern-Simons perturbation theory on compact spacetime 3-manifolds with quantisation around an arbitrary flat gauge field isolated up to gauge transformations, pointing out that previous results on the finiteness and formal metric-independence of perturbative expansions of the partition function continue to hold.13 pages, latex. To appear in Lett.Math.PhysHigh Energy Physics - TheoryDifferential Geometrytext