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Quasi-isometry and commensurability classification of certain right-angled Coxeter groups

Groups acting on CAT(0) spaces September 27, 2016 - September 30, 2016

September 30, 2016 (03:30 PM PDT - 04:20 PM PDT)
Speaker(s): Anne Thomas (University of Sydney)
Location: MSRI: Simons Auditorium
  • non-positive curvature

  • CAT(0) space

  • Symmetric space

  • buildings and complexes

  • group actions

Primary Mathematics Subject Classification
Secondary Mathematics Subject Classification No Secondary AMS MSC



Bowditch's JSJ tree is a quasi-isometry invariant for one-ended hyperbolic groups, which uses the local cut point structure of their visual boundary.  We compute this tree for a large family of hyperbolic right-angled Coxeter groups, and identify a subfamily for which this tree is a complete quasi-isometry invariant.  We then investigate the commensurability classification of groups in this subfamily.  For our work on commensurability, a key step is proving that these Coxeter groups are virtually geometric amalgams of surfaces.  This is joint work with Pallavi Dani (Louisiana State University) and Emily Stark (University of Haifa).


26822?type=thumb Thomas.Notes 1.98 MB application/pdf Download
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H.264 Video 14622.mp4 249 MB video/mp4 rtsp://videos.msri.org/data/000/026/675/original/14622.mp4 Download
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