A uniform chain whose inverse semigroup has no chart.
Let be a finite group and let denote the set of conjugacy class sizes of . Thompson’s conjecture states that if is a centerless group and is a non-abelian simple group satisfying , then . In this paper, we investigate a variation of this conjecture for some symmetric groups under a weaker assumption. In particular, it is shown that if and only if and has a special conjugacy class of size , where is a prime number. Consequently, if is a centerless group with , then .
In this article we prove an effective version of the classical Brauer’s Theorem for integer class functions on finite groups.
We give a simple proof of a result of R. Rochberg and M. H. Taibleson that various maximal operators on a homogeneous tree, including the Hardy-Littlewood and spherical maximal operators, are of weak type (1,1). This result extends to corresponding maximal operators on a transitive group of isometries of the tree, and in particular for (nonabelian finitely generated) free groups.
Torsion-free covers are considered for objects in the category Objects in the category are just maps in -Mod. For we find necessary and sufficient conditions for the coGalois group associated to a torsion-free cover, to be trivial for an object in Our results generalize those of E. Enochs and J. Rado for abelian groups.
The notions of nearly-maximal and near Frattini subgroups considered by J.B. Riles in [20] and the natural related notions are characterized for abelian groups.