The diameter of proper power graphs of some finite groups

Th e power graph P(G) of finite group G is a simple graph whose vertex set is G and two distinct elements a and b are adjacent if and only if one of them is a power of the other. Th e proper power graph of G denoted by P*(G) is a graph which is which is obtained by deleting the identity vertex (the identity element of G). In this paper, we determine the diameter of proper power graphs of some finite groups.