When unit graphs are isomorphic to unitary Cayley graphs of rings?
Abstract
Let R be a ring with identity. The unit (respectively, unitary Cayley) graph of R is a simple graph G(R) (respectively, Γ(R)) with vertex set R, where two distinct vertices x and y are adjacent if and only if x+y (respectively, x−y) is a unit of R. In this paper, we explore when G(R) and Γ(R) are isomorphic for a finite ring R. Among other results, we prove that G(R) is isomorphic to Γ(R) for a finite ring R if and only if char(R/J(R))=2 or R/J(R)≅ℤ2×S, where J(R) is the Jacobson radical of R and S is a finite ring.
Communicated by Tai Huy Ha