## Alexander Zakharov (University of Porto): On finitely generated submonoids of free groups

 Wednesday, 11. April 2018, 10:00 - 12:00
Abstract. Free groups are some of the most basic and important examples of groups. All subgroups of free groups are free, by a theorem of Nielsen and Schreier, and finitely generated ones have nice algorithmic properties, since they can be represented by Stallings automata. However, the structure of finitely generated submonoids of free groups is much more complicated. In particular, these include all finitely generated submonoids of free monoids, which can be even not finitely presented, let alone free. The isomorphism problem is one of the most natural algorithmic questions about groups or monoids. We solve the isomorphism problem for a big class of submonoids of free groups, which can be described in a few different ways. This is a joint work with Pedro Silva.
Location : Bolyai Intézet, I. emelet, Riesz terem, Aradi Vértanúk tere 1., Szeged