Kadison's problem for type III subfactors and the bicentralizer conjecture

A Marrakchi - Inventiones mathematicae, 2025 - Springer
Abstract In 1967, Kadison asked “if\(N\) is a subfactor of the factor\(M\) for which\(N'\cap M\)
consists of scalars, will some maximal abelian*-subalgebra of\(N\) be a maximal abelian …

First ℓ2-Betti numbers and proper proximality

C Ding - Advances in Mathematics, 2024 - Elsevier
We show that for a countable exact group, having positive first ℓ 2-Betti number implies
proper proximality in this sense of [3]. This is achieved by showing a cocycle superrigidity …

Some classes of smooth bimodules over II1 factors and their associated 1-cohomology spaces

P Hiatt, J Peterson, S Popa - Journal of Functional Analysis, 2024 - Elsevier
We study several classes of Banach bimodules over a II 1 factor M, endowed with topologies
that make them “smooth” with respect to L p-norms implemented by the trace τ on M. Thus …

On the isomorphism class of -Gaussian W-algebras for infinite variables

M Caspers - Comptes Rendus. Mathématique, 2023 - comptes-rendus.academie-sciences …
Let Mq (HR) be the q-Gaussian von Neumann algebra associated with a separable infinite
dimensional real Hilbert space HR where− 1< q< 1. We show that Mq (HR) ̸≃ M0 (HR) for …

Proper proximality among various families of groups

C Ding, SK Elayavalli - Groups, Geometry, and Dynamics, 2024 - ems.press
In this paper, the notion of proper proximality (introduced by Boutonnet, Ioana, and Peterson
[Ann. Sci. Éc. Norm. Supér.(4) 54 (2021), 445–482]) is studied and classified in various …

Measure equivalence rigidity via s-malleable deformations

D Drimbe - Compositio Mathematica, 2023 - cambridge.org
We single out a large class of groups are 'rigid'. In particular, we provide an alternative
solution to a question of Popa that was recently answered by Ding, Kunnawalkam Elayavalli …

Structure of Relatively Biexact Group von Neumann Algebras

C Ding, SK Elayavalli - Communications in Mathematical Physics, 2024 - Springer
Using computations in the bidual of B (L 2 M) we develop a new technique at the von
Neumann algebra level to upgrade relative proper proximality to full proper proximality. This …

Biexact von Neumann algebras

C Ding, J Peterson - arXiv preprint arXiv:2309.10161, 2023 - arxiv.org
We introduce the notion of biexactness for general von Neumann algebras, naturally
extending the notion from group theory. We show that biexactness implies solidity for von …

[HTML][HTML] Hypertrace and entropy gap characterizations of property (T) for II1 factors

S Zhou - Journal of Functional Analysis, 2024 - Elsevier
We establish a hypertrace characterization of property (T) for II 1 factors: Given a II 1 factors
M, M does not have property (T) if and only if there exists a von Neumann algebra A with …

Measure equivalence embeddings of free groups and free group factors

T Berendschot, S Vaes - arXiv preprint arXiv:2212.11704, 2022 - arxiv.org
We give a simple and explicit proof that the free group $\mathbb {F} _2 $ admits a measure
equivalence embedding into any nonamenable locally compact second countable (lcsc) …