2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/70615For a knot K in $S^3$ and a regular representation $ρ$ of its group $G_K$ into SU(2) we construct a non abelian Reidemeister torsion on the first twisted cohomology group of the knot exterior. This non abelian Reidemeister torsion provides a volume form on the SU(2)-representation space of $G_K$. In another way, we construct according to Casson--or more precisely taking into account Lin's and Heusener's further works--a volume form on the SU(2)-representation space of $G_K$. Next, we compare these two apparently different points of view--the first by means of the Reidemeister torsion and the second defined ``a la Casson"--and finally prove that they define the same topological knot invariant.36 pages, 2 figures. to appear in Ann. Institut FourierGeometric TopologyAlgebraic Topology57M25; 57Q10; 57M27text