Submanifold projections and hyperbolicity in ${\rm Out}(F_n)$

Ursula Hamenstädt; Sebastian Hensel

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arXiv · 2403.18698

Submanifold projections and hyperbolicity in ${\rm Out}(F_n)$

Ursula Hamenstädt·Sebastian Hensel

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Abstract

The free splitting graph of a free group $F_n$ with $n\geq 2$ generators is a hyperbolic ${\rm Out}(F_n)$-graph which has a geometric realization as a sphere graph in the connected sum of $n$ copies of $S^1\times S^2$. We use this realization to construct submanifold projections of the free splitting graph into the free splitting graphs of proper free factors. This is used to construct for $n\geq 3$ a new hyperbolic ${\rm Out}(F_n)$-graph. If $n=3$, then every exponentially growing element acts on this graph with positive translation length.

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BibTeX RIS

Ursula Hamenstädt, Sebastian Hensel. 2024-03-27. Submanifold projections and hyperbolicity in ${\rm Out}(F_n)$. https://arxiv.org/abs/2403.18698

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