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SUMMARY:Richard Webb (University of Manchester)
DTSTART:20200519T140000Z
DTEND:20200519T151500Z
DTSTAMP:20260423T024614Z
UID:rlgts/3
DESCRIPTION:Title: <a href="https://researchseminars.org/talk/rlgts/3/">Qu
 asimorphisms on diffeomorphism groups</a>\nby Richard Webb (University of 
 Manchester) as part of Regensburg low-dimensional geometry and topology se
 minar\n\n\nAbstract\nI will explain how to construct an unbounded quasimor
 phism on the group of isotopically-trivial diffeomorphisms of a surface of
  positive genus. As a corollary the commutator length and fragmentation no
 rm are both (stably) unbounded\, which solves a problem of Burago--Ivanov-
 -Polterovich. The proof uses a new hyperbolic graph on which these groups 
 act by isometries\, which is inspired by techniques from mapping class gro
 ups. This is joint work with Jonathan Bowden and Sebastian Hensel.\n
LOCATION:https://researchseminars.org/talk/rlgts/3/
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