Let $G$ be a finite group and $pi_{e}(G)$ be the set of orders of all elements in $G$. The set $pi_{e}(G)$ determines the prime graph (or Grunberg-Kegel graph) $Gamma(G)$ whose vertex set is $pi(G)$, the set of primes dividing the order of $G$, and two vertices $p$ and $q$ are adjacent if and only if $pqinpi_{e}(G)$. The degree $deg(p)$ of a vertex $pin pi(G)$, is the number of edges incident...

This paper begins the classification of all edge-primitive 3-arc-transitive graphs by classifying such where automorphism group is an almost simple with socle alternating or sporadic group, and classical a vertex-stabiliser acting faithfully on set neighbours.

Let G be a simple primitive subgroup of Sn, speciied in terms of a set of generating permutations. If jGj n 5 , eecient algorithms are presented that nd \the most natural permutation representation" of G. For example, if G is a classical group then we nd a suitable projective space underlying G. A number of related questions are considered. Our notion of \eeciency" takes into account many exist...

Let G be a finite group , in this paper using the order and largest element order of G we show that every finite group with the same order and largest element order as G 2 (q), where q 11 is necessarily isomorphic to the group G 2 (q)

We study pairs (G,A) where G is a finite group and A < G is maximal, satisfying ⋃ g∈G (Ax) = G − {1G} for all x ∈ G − A. We prove that this condition defines a class of permutation groups, denoted CCI, which is a subclass of the class of primitive permutation groups. We prove that CCI contains the class of 2-transitive groups. We also prove that groups in CCI are either affi ne or almost simple...

Proposition 1. (Grunewald [5, Proposition B]) Let F be a free group of rank k ≥ 2, generated by {s1, . . . , sk}. Let r1, . . . , rm be words over {s1, . . . , sk} ±1 and R their normal closure 〈〈r1, . . . , rm〉〉F in F . Let H be the group with presentation 〈s1, . . . , sk | r1, . . . , rm〉 and φ the canonical epimorphism φ : F → H ∼= F/R. Let F be a free group of rank k generated by {t1, . . ....