Higher Kazhdan projections and delocalised ℓ^ 2-Betti numbers

2024/05/06 by Pooya, Sanaz, Wang, Hang · 2 citations
#19D55 #20F65 #46L80 #FOS: Mathematics #Group Theory (math.GR) #K-Theory and Homology (math.KT) #Operator Algebras (math.OA)

paper · doi:10.48550/arxiv.2405.03837

Abstract

We provide an explicit description of the K-classes of higher Kazhdan projections in degrees greater than 0 for specific free product groups and Cartesian product groups. Employing this description, we obtain new calculations of Lott's delocalised ℓ²-Betti numbers. Notably, we establish the first non-vanishing results for infinite groups.

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