7 papers
Spectral Theory for Borel PMP Graphs
Cecelia Higgins, Pieter Spaas, Alexander Tenenbaum
We initiate a systematic study of spectral theory for bounded-degree Borel pmp graphs. Specifically, we study spectral properties of the associated adjacency and Laplacian operator…
Hilbert--Schmidt stability for graph products
Pieter Spaas
In this short note we prove Hilbert--Schmidt stability for graph products of abelian groups and -algebras on chordal graphs. In particular, this shows that right-angled Artin…
On compact extensions of tracial -dynamical systems
Asgar Jamneshan, Pieter Spaas
We establish several classification results for compact extensions of tracial -dynamical systems and for relatively independent joinings thereof for actions of arbitrary discr…
Gap-preserving reductions and RE-completeness of independent set games
Laura ManÄinska, Pieter Spaas, Taro Spirig +1
In complexity theory, gap-preserving reductions play a crucial role in studying hardness of approximation and in analyzing the relative complexity of multiprover interactive proof…
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…
Trace spaces of full free product -algebras
Adrian Ioana, Pieter Spaas, Itamar Vigdorovich
We study the space of traces associated with arbitrary full free products of unital, separable -algebras. We show that, unless certain basic obstructions (which we fully chara…