The Fitting class generated by the -perfect groups
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...
A subgroup of a finite group is weakly-supplemented in if there exists a proper subgroup of such that . In the paper it is proved that a finite group is -nilpotent provided is the smallest prime number dividing the order of and every minimal subgroup of is weakly-supplemented in where is a Sylow -subgroup of . As applications, some interesting results with weakly-supplemented minimal subgroups of are obtained.
In this paper we study the set of Fitting classes which are right extensible by soluble groups ordered by the inclusion relation. The consideration of the associated lattices gives rise to new Fitting classes and it allows to obtain some injectivity criteria for general Fitting classes.