We introduce and study the lattice of normal subgroups of a group G that determine solitary quotients. It is closely connected to the well-known lattice of solitary subgroups of G, see [Kaplan G., Levy D., Solitary subgroups, Comm. Algebra, 2009, 37(6), 1873–1883]. A precise description of this lattice is given for some particular classes of finite groups.
In this paper we will prove that if G is a finite group, X a subnormal subgroup of X F*(G) such that X F*(G) is quasinilpotent and Y is a quasinilpotent subgroup of NG(X), then Y F*(NG(X)) is quasinilpotent if and only if Y F*(G) is quasinilpotent. Also we will obtain that F*(G) controls its own fusion in G if and only if G = F*(G).
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.