2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/74297We prove that the isomorphism problem for finitely generated fully residually free groups is decidable. We also show that each finitely generated fully residually free group G has a decomposition that is invariant under automorphisms of G, and obtain a structure theorem for the group of outer automorphisms Out(G).26 pagesGroup Theory20E36; 20F65text