Fuchs' problem for endomorphisms of nonabelian groups

Abstract

In 1960, László Fuchs posed the problem of determining which groups $G$ are realizable as the group of units in some ring $R$. In \cite{chebolu2022fuchs}, we investigated the following variant of Fuchs' problem, for abelian groups: which groups $G$ are realized by a ring $R$ where every group endomorphism of $G$ is induced by a ring endomorphism of $R$? Such groups are called fully realizable. In this paper, we answer the aforementioned question for several families of nonabelian groups: symmetric, dihedral, quaternion, alternating, and simple groups; almost cyclic $p$-groups; and groups whose Sylow $2$-subgroup is either cyclic or normal and abelian. We construct three infinite families of fully realizable nonabelian groups using iterated semidirect products.

27 pages, accepted for publication in the Journal of Algebra