Aspherical manifolds with nonvanishing tautological classes

Abstract

For every even integer $m\ge 2$, we construct a closed, orientable, smooth, aspherical $(2m+1)$-manifold whose fundamental group has nontrivial center and for which infinitely many tautological classes in the ${\mathbb{F}}_2$-cohomology of the classifying space of its group of homotopically trivial diffeomorphisms are nonzero and not nilpotent. Specializing the calculation to cohomological degree $0$ gives examples of such manifolds that do not bound compact smooth manifolds. These provide counterexamples to a conjecture of Hebestreit--Land--Lück--Randal-Williams.

arXiv comment11 pages