Undirected power graph of a group

Definition
Let $$G$$ be a group. The undirected power graph of $$G$$ is the graph whose vertices are the elements of $$G$$ and where, given two distinct vertices $$g$$ and $$h$$, there is an edge between $$g$$ and $$h$$ if either $$g$$ is a power of $$h$$ or $$h$$ is a power of $$g$$.

Related notions

 * Directed power graph of a group

Facts

 * Undirected power graph determines directed power graph for finite group
 * Finite groups are 1-isomorphic iff their directed power graphs are 1-isomorphic