On the power-commutative kernel of locally nilpotent groups.
Let be a group and be an integer greater than or equal to . is said to be -permutable if every product of elements can be reordered at least in one way. We prove that, if has a centre of finite index , then is -permutable. More bounds are given on the least such that is -permutable.
In this note we determine explicit formulas for the relative commutator of groups with respect to the subvarieties of -nilpotent groups and of -solvable groups. In particular these formulas give a characterization of the extensions of groups that are central relatively to these subvarieties.
Let be a group and an integer . We say that has the -permutation property if, for any elements in , there exists some permutation of , such that . We prouve that every group is an FC-nilpotent group of class , and that a finitely generated group has the -permutation property (for some ) if, and only if, it is abelian by finite. We prouve also that a group if, and only if, its derived subgroup has order at most 2.
The Ore conjecture, posed in 1951, states that every element of every finite non-abelian simple group is a commutator. Despite considerable effort, it remains open for various infinite families of simple groups. In this paper we develop new strategies, combining character-theoretic methods with other ingredients, and use them to establish the conjecture.