Configuration Equivalence is not Equivalent to Isomorphism

TL;DR

This paper demonstrates that configuration equivalence does not necessarily imply group isomorphism by providing counterexamples and exploring subgroup properties, thereby clarifying the relationship between these concepts in group theory.

Contribution

It introduces non-isomorphic, solvable, and amenable groups that are configuration equivalent, answering an open question and analyzing subgroup structures in such groups.

Findings

Configuration equivalence does not imply isomorphism.

Counterexamples of non-isomorphic, solvable, amenable groups with the same configuration.

Groups with the same class numbers are two-sided equivalent.

Abstract

Giving a condition for the the amenability of groups, Rosenblatt and Willis, first introduced the concept of configuration. From the beginning of the theory, the question whether the concept of configuration equivalence coincides with the concept of group isomorphism was posed. We negatively answer this open question by introducing two non-isomorphic, solvable and hence amenable groups which are configuration equivalent. Also, we will study some types of subgroups in configuration equivalent groups. In particular, we will prove this conjecture, due to Rosenblatt and Willis, that configuration equivalent groups, both include the free non-Abelian group of same rank or not. Finally, we prove that two-sided equivalent groups have same class numbers.