On the difference of the enhanced power graph and the power graph of a finite group

The difference graph D ( G ) of a finite group G is the difference of the enhanced power graph of G and the power graph of G , where all isolated vertices are removed. In this paper we study the connectedness and perfectness of D ( G ) with respect to various properties of the underlying group G . We also find several connections between the difference graph of G and the Gruenberg-Kegel graph of G . We also examine the operation of twin reduction on graphs, a technique which produces smaller graphs which may be easier to analyze. Applying this technique to simple groups can have a number of outcomes, not fully understood, but including some graphs with large girth. (c) 2024 Elsevier Inc. All rights are reserved, including those for text and data mining, AI training, and similar technologies.