In this paper, we prove the conjectures made in a joint paper of the author with Carlson and Robinson, on the vanishing of cohomology of a nite group G. In particular, we prove that if k is a eld of characteristic p, then every non-projective kG-module M in the principal block has nontrivial cohomology in the sense that H (G;M) 6= 0, if and only if the centralizer in G of every element of order...

Suppose that G is an abelian p-separable group and R is a commutative unital ring of prime characteristic p. It is proved that if Rp i possesses nilpotent elements for each natural number i, then the normalized Sylow p-subgroup S(RG) in the group ring RG is torsion-complete if and only if G is p-bounded. This supplies our recent results from Acta Math. Hung. (1997), Ric. Mat. (2002), Tamkang J....

Let G be an arbitrary group. We show that if the Fitting subgroup of G is nilpotent then it is definable. We show also that the class of groups whose Fitting subgroup is nilpotent of class at most n is elementary. We give an example of a group (arbitrary saturated) whose Fitting subgroup is definable but not nilpotent. Similar results for the soluble radical are given.

We consider expansive group actions on a compact metric space containing special fixed point denoted by [Formula: see text], and endomorphisms of such systems whose forward trajectories are attracted toward text]. Such called asymptotically nilpotent, we study the conditions in which they that is, map entire to text] finite number iterations. show for large class discrete groups, this property ...

In this paper, we prove the conjectures made in a joint paper of the author with Carlson and Robinson, on the vanishing of cohomology of a nite group G. In particular, we prove that if k is a eld of characteristic p, then every non-projective kG-module M in the principal block has nontrivial cohomology in the sense that H (G; M) 6 = 0, if and only if the centralizer in G of every element of ord...