The Euler class and periodicity of group cohomology.
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.
For a finite group and a fixed Sylow -subgroup of , Ballester-Bolinches and Guo proved in 2000 that is -nilpotent if every element of with order lies in the center of and when , either every element of with order lies in the center of or is quaternion-free and is -nilpotent. Asaad introduced weakly pronormal subgroup of in 2014 and proved that is -nilpotent if every element of with order is weakly pronormal in and when , every element of with order is also...