Acyclicity in bounded cohomology – Marco Moraschini (Università di Bologna)


Aula Seminari - Dipartimento di Matematica


Bounded cohomology is an invariant of groups introduced by Johnson in the 70s and then extensively studied both in geometric group theory and in low dimensional topology after the pioneering paper by Gromov (1982).

Bounded cohomology is known to vanish in presence of amenable groups, but it is hard to compute for most groups (e.g. we do not know the full bounded cohomology of the non-abelian free group with two generators).

In this talk we will introduce bounded cohomology and discuss some recent computations involving boundedly acyclic groups (i.e. groups with trivial bounded cohomology in all positive degrees). We will report some results in collaboration with Francesco Fournier-Facio, Clara Löh and George Raptis.

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