Homotopy classification of $4$-manifolds with fundamental group $\mathbb{Z}/p \rtimes \mathbb{Z}$

Abstract

For an odd prime $p$, we show that the homotopy type of a closed $4$-manifold with fundamental group $\mathbb{Z}/p \rtimes \mathbb{Z}$ is determined by its quadratic $2$-type together with an additional $\mathbb{Z}/p$-valued intersection form. We also give a generalization to infinite groups of a result of Hambleton--Kreck on the polarized homotopy classification of Poincar\'e $4$-complexes, and we prove some partial results on the homotopy classification that are applicable more generally.