some results on divisibility graph in some classes of finite groups

A nite group g is called an f????group, if for every x; y 2 g nz(g), cg(x)  cg(y) implies that cg(x) = cg(y). the graph d(g) iscalled the divisibility graph of g if its vertex set is the non-central conjugacyclass sizes of g and there is an edge between vertices a and b if and only if ajbor bja. we determine the number of connected components of the divisibilitygraph d(g) where g is an f????group.