Finiteness properties of automorphism spaces of manifolds with finite fundamental group

Abstract

AbstractGiven a closed smooth manifoldMof even dimension$$2n\ge 6$$2n≥6with finite fundamental group, we show that the classifying space$$B\textrm{Diff}(M)$$BDiff(M)of the diffeomorphism group ofMis of finite type and has finitely generated homotopy groups in every degree. We also prove a variant of this result for manifolds with boundary and deduce that the space of smooth embeddings of a compact submanifold$$N\subset M$$N⊂Mof arbitrary codimension intoMhas finitely generated higher homotopy groups based at the inclusion, provided the fundamental group of the complement is finite. As an intermediate result, we show that the group of homotopy classes of simple homotopy self-equivalences of a finite CW complex with finite fundamental group is up to finite kernel commensurable to an arithmetic group.