Abstract (EN):
We prove that, given a finitely generated subgroup H of a free group F, the following questions are decidable: is H closed (dense) in F for the pro-(met)abelian topology? is the closure of H in F for the pro-(met)abelian topology finitely generated? We show also that if the latter question has a positive answer, then we can effectively construct a basis for the closure, and the closure has decidable membership problem in any case. Moreover, it is decidable whether H is closed for the pro-V topology when V is an equational pseudovariety of finite groups, such as the pseudovariety S-k of all finite solvable groups with derived length <= k. We also connect the pro-abelian topology with the topologies defined by abelian groups of bounded exponent.
Language:
English
Type (Professor's evaluation):
Scientific
No. of pages:
21