Some results on -solvable and supersolvable groups.
In this Note conditions for the existence of a normal -complement and for the supersolubility of a finite group are given.
Sia un gruppo non abeliano né hamiltoniano, ed un intero . Si dice che appartiene a se tutti i sottogruppi non normali di hanno ordine . Sia un numero primo. In questa Nota vengono determinati: 1) tutti i -gruppi in (Teoremi 1 e 2); 2) tutti i -gruppi in per e (Teorema 3); 3) tutti i gruppi di esponente appartenenti ad (Teorema 4).
In this paper we study finite non abelian solvable groups in which every proper normal subgroup is abelian, and non-solvable ones in which every proper normal subgroup is abelian and has a basis of at most two elements.
We prove that in the Mathieu groups there is a unique conjugacy class of nilpotent self-normalizing subgroups, the class of the 2-Sylow subgroups. In the Janko group there are no nilpotent self-normalizing subgroups.
Let be a group and a prime. The subgroup generated by the elements of order different from is called the Hughes subgroup for exponent . Hughes [3] made the following conjecture: if is non-trivial, its index in is at most . There are many articles that treat this problem. In the present Note we examine those of Strauss and Szekeres [9], which treats the case and arbitrary, and that of Hogan and Kappe [2] concerning the case when is metabelian, and arbitrary. A common proof is...
Nel presente lavoro vengono dimostrati teoremi d'esistenza di -complementi normali nei gruppi finiti.