$\mathbb{Z}/p^r$-hyperbolicity via homology

Abstract

We show that the homotopy groups of a Moore space $P^n(p^r)$, where $p^r\ne 2$, are $\mathbb{Z}/p^s$-hyperbolic for $s\le r$. Combined with work of Huang-Wu, Neisendorfer, and Theriault, this completely resolves the question of when such a Moore space is $\mathbb{Z}/p^s$-hyperbolic for $p\ge 5$, or when $p=2$ and $r\ge 6$. We also give a criterion in ordinary homology for a space to be $\mathbb{Z}/p^r$-hyperbolic, and deduce some examples.

31 pages. Comments welcome! v2: minor tweaks to include the case p^s=2 and its consequences (originally due to Zhu-Pan), edits to introduction