2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/144538We prove the following results: let x,y be (n,n) complex matrices such that x,y,xy have no eigenvalue in ]-infinity,0] and log(xy)=log(x)+log(y). If n=2, or if n>2 and x,y are simultaneously triangularizable, then x,y commute. In both cases we reduce the problem to a result in complex analysis.Minor corrections and a new resultRings and Algebras39B42text