1 citations · 1 across the 6 of their papers we have counts for
7 papers
Borel complexity for product of trees and commuting partial maps
Koichi Oyakawa
We prove that every acylindrical action on uniformly locally finite product of trees induces the hyperfinite orbit equivalence relation on the Roller boundary. As a byproduct, we c…
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…
Hyperfiniteness of the boundary action of virtually special groups
Koichi Oyakawa
We prove that for any countable group acting virtually specially on a CAT(0) cube complex, the orbit equivalence relation induced by its action on the Roller boundary is hyperfinit…
Hyperfiniteness for group actions on trees
Srivatsav Kunnawalkam Elayavalli, Koichi Oyakawa, Forte Shinko +1
We identify natural conditions for a countable group acting on a countable tree which imply that the orbit equivalence relation of the induced action on the Gromov boundary is Bore…
Hyperfiniteness of boundary actions of acylindrically hyperbolic groups
Koichi Oyakawa
We prove that for any countable acylidrically hyperbolic group , there exists a generating set of such that the corresponding Cayley graph is hyperbolic, $|\par…
Small cancellation groups are bi-exact
Koichi Oyakawa
We prove that finitely generated (not necessarily finitely presented) -groups are bi-exact. This is a new class of bi-exact groups.
Bi-exactness of relatively hyperbolic groups
Koichi Oyakawa
We prove that finitely generated relatively hyperbolic groups are bi-exact if and only if all peripheral subgroups are bi-exact. This is a generalization of Ozawa's result which cl…