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arXiv · 2405.03837

Higher Kazhdan projections and delocalised $\ell^ 2$-Betti numbers

Sanaz Pooya·Hang Wang
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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 $\ell^2$-Betti numbers. Notably, we establish the first non-vanishing results for infinite groups.

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Sanaz Pooya, Hang Wang. 2026-05-26. Higher Kazhdan projections and delocalised $\ell^ 2$-Betti numbers. https://doi.org/10.2140/akt.2026.11.395

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