2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/112620We study automorphisms of the free associative algebra K<x,y,z> over a field K which fix the variable z. We describe the structure of the group of z-tame automorphisms and derive algorithms which recognize z-tame automorphisms and z-tame coordinates.Rings and AlgebrasPrimary 16S10. Secondary 16W20; 16Z05text