Systoles of Hyperbolic Manifolds
We show that for every $n\geq 2$ and any $ε>0$ there exists a compact hyperbolic $n$-manifold with a closed geodesic of length less than $ε$. When $ε$ is sufficiently small these manifolds are non-arithmetic, and they are obtained by a generalised inbreeding construction which was first suggested by Agol for $n=4$. We also show that for $n\geq 3$ the volumes of these manifolds grow at least as $1/ε^{n-2}$ when $ε\to 0$.
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