Let G be a finite group, and let F be a formation of finite group. We say that a subgroup H of G is p F -normal in G if there exists a normal subgroup T of G such that HT is a permutable Hall subgroup of G and G G H H T H / ) ( is contained in the F-hypercenter ) / ( G F H G Z of G H G / . In this note, we get some results about the p F -normal subgroups and then use them to study the structure...

A p-regular element in a finite group is an element of order not divisible by the prime number p. We show that for every prime p and every finite simple group S, a fair proportion of elements of S is p-regular. In particular, we show that the proportion of p-regular elements in a finite classical simple group (not necessarily of characteristic p) is greater than 1/(2n), where n− 1 is the dimens...

In [2], we gave algorithms to calculate c(G), q(G) and p(G) for a finite group G. In this paper, we show that for a finite p-group G, where p is a prime, q(G) = p(G). Moreover, for odd prime p, c(G) = q(G) = p(G). 2000 Mathematics Subject Classification: primary 20D15; secondary 20B05, 20C15

Let p be a prime. It is proved that a non-trivial word w from a free group F has finite width in every finitely generated pro-p group if and only if w 6∈ (F ′)pF ′′. Also it is shown that any word w has finite width in a compact p-adic group.