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SUMMARY:Quasi-isometric rigidity of graphs of free groups with cyclic edge
  groups - Daniel Woodhouse (University of Oxford)
DTSTART:20201016T124500Z
DTEND:20201016T134500Z
UID:TALK152821@talks.cam.ac.uk
CONTACT:76015
DESCRIPTION:Let F be a finitely rank free group. Let w_1 and w_2 be suitab
 le random/generic elements in F. Consider the HNN extension G generated by
  F and a stable letter t\, with relation t w_1 t^{-1} = w_2 . It is known 
 from existing results that G will be 1-ended and hyperbolic. We have shown
  that G is quasi-isometrically rigid. That is to say that if a f.g. group 
 H is quasi-isometric to G\, then G and H are virtually isomorphic. The ful
 l result is for finite graphs of groups with virtually free vertex groups 
 and two-ended edge groups\, but the statement is more technical -- not all
  such groups are QI-rigid. The main argument involves applying a new proof
  of Leighton's graph covering theorem.\n\nThis is joint work with Sam Shep
 herd.
LOCATION:Zoom: https://maths-cam-ac-uk.zoom.us/j/91636583222
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