2 citations · 4 across the 11 of their papers we have counts for
12 papers
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…
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…
Gap-preserving reductions and RE-completeness of independent set games
Laura Mančinska, 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…
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…
Local Hilbert--Schmidt stability
Francesco Fournier-Facio, Maria Gerasimova, Pieter Spaas
We introduce a notion of local Hilbert--Schmidt stability, motivated by the recent definition by Bradford of local permutation stability, and give examples of (non-residually finit…
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…
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…
Stable decompositions and rigidity for products of countable equivalence relations
Pieter Spaas
We show that the stabilization of any countable ergodic p.m.p. equivalence relation which is not Schmidt, i.e. admits no central sequences in its full group, always gives rise to a…
Cohomological obstructions to lifting properties for full group C-algebras
Adrian Ioana, Pieter Spaas, Matthew Wiersma
We develop a new method, based on non-vanishing of second cohomology groups, for proving the failure of lifting properties for full C-algebras of countable groups with (relativ…
II factors with exotic central sequence algebras
Adrian Ioana, Pieter Spaas
We provide a class of separable II factors whose central sequence algebra is not the "tail" algebra associated to any decreasing sequence of von Neumann subalgebras of .…
A class of II factors with a unique McDuff decomposition
Adrian Ioana, Pieter Spaas
We provide a fairly large class of II factors such that has a unique McDuff decomposition, up to isomorphism, where denotes the hyperfinite II f…
Non-classification of Cartan subalgebras for a class of von Neumann algebras
Pieter Spaas
We study the complexity of the classification problem for Cartan subalgebras in von Neumann algebras. We construct a large family of II factors whose Cartan subalgebras up to u…