4 papers · 1 filter
Hyperfiniteness of boundary actions via tree decompositions
Chris Karpinski, Bobby Miraftab
We study conditions for a countable group acting on a connected locally finite hyperbolic graph to induce a hyperfinite orbit equivalence relation on the Gromov boundary of the gra…
Graphical small cancellation and hyperfiniteness of boundary actions
Chris Karpinski, Damian Osajda, Koichi Oyakawa
We study actions of (infinitely presented) graphical small cancellation groups on the Gromov boundaries of their coned-off Cayley graphs. We show that a class of graphical small ca…
Conjugacy Problem for Dehn Twists of Free Products of Free Abelian Groups
Amir Y. Weiss Behar, Chris Karpinski, Bratati Som
We show solubility of the conjugacy problem for Dehn twist automorphisms of finitely generated free products of free abelian groups.
Weak Tits alternative for groups acting geometrically on buildings
Chris Karpinski, Damian Osajda, Piotr Przytycki
We show that if a group acts geometrically by type-preserving automorphisms on a building, then satisfies the weak Tits alternative, namely, that is either virtually ab…