4 papers · 1 filter
Virtual homological torsion in graphs of free groups with cyclic edge groups
Dario Ascari, Jonathan Fruchter
Let be a hyperbolic group that splits as a graph of free groups with cyclic edge groups. We prove that, unless is isomorphic to a free product of free and surface groups, e…
Dehn functions of subgroups of products of free groups. Part II: Precise computations
Dario Ascari, Federica Bertolotti, Giovanni Italiano +2
We prove that the Bridson-Dison group has quartic Dehn function, thereby providing the first precise computation of the Dehn function of a subgroup of a direct product of free grou…
Dehn functions of subgroups of products of free groups. Part I: Uniform upper bounds
Dario Ascari, Federica Bertolotti, Giovanni Italiano +2
Subgroups of direct products of finitely many finitely generated free groups form a natural class that plays an important role in geometric group theory. Its members include fundam…
Weakly bounded cohomology classes and a counterexample to a conjecture of Gromov
Dario Ascari, Francesco Milizia
We exhibit a finitely presented group whose second cohomology contains a weakly bounded, but not bounded, class. As an application, we disprove a long-standing conjecture of Gromov…