2025/07/07 by Drimbe, Daniel, Vaes, Stefaan · 1 citation
#FOS: Mathematics #Group Theory (math.GR) #Operator Algebras (math.OA)
paper · doi:10.48550/arxiv.2507.04691
A variant of Gromov's notion of measure equivalence for groups has been introduced for II1 factors under different names. We propose the terminology of W*-correlated II1 factors. We prove rigidity results up to W*-correlations for tensor products and graph products of II1 factors. As a consequence, we construct the first uncountable family of discrete groups Γ that are not von Neumann equivalent, which means that their group von Neumann algebras L(Γ) are not W*-correlated, and which implies that these groups are neither measure equivalent, nor have isomorphic or virtually isomorphic group von Neumann algebras.