Higher Kazhdan projections, ${\ell }_2$-Betti numbers and Baum-Connes conjectures

Kang Li, Piotr W. Nowak, Sanaz Pooya

We introduce higher-dimensional analogs of Kazhdan projections in matrix algebras over group $C^{\ast }$-algebras and Roe algebras. These projections are constructed in the framework of…