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arXiv · 2605.21734

Virtual specialness of the double

Changqian Li
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Abstract

Let $G$ be a virtually compact special Gromov-hyperbolic group. We prove that the double $G *_H G$ along a quasiconvex subgroup $H$ is virtually compact special. More generally, we show that if a finite graph of groups has constant vertex groups, with each vertex group virtually compact special Gromov-hyperbolic and each edge group quasiconvex in its adjacent vertex groups, then its fundamental group is virtually compact special.

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Changqian Li. 2026-05-20. Virtual specialness of the double. https://arxiv.org/abs/2605.21734

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