The Isomorphism Problem for Higman-Thompson groups

Abstract

We prove that the Higman–Thompson groups View the MathML sourceGn,r+ and View the MathML sourceGm,s+ are isomorphic if and only if m=nm=n and gcd(n−1,r)=gcd(n−1,s)gcd(n−1,r)=gcd(n−1,s).