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Hydra groups

We give examples of CAT(0), biautomatic, free-by-cyclic, one-relator groups which have finite-rank free subgroups of huge (Ackermannian) distortion. This leads to elementary examples of groups whose Dehn functions are similarly extravagant. This behaviour originates in manifestations of Hercules-versus-the-hydra battles in string-rewriting.

4 nodes3 linksoverview mapHydra groups
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Co-authorshipAuthorshipAuthorshipTopic signalWHydra groupspreprint / 2010AWill DisonResearcherATim RileyResearcherTmath.GR2651 works
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Hydra groups

preprint / 2010

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