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CATEGORIES:Differential Geometry and Topology Seminar
SUMMARY:Mapping class groups for simply connected 4-manifo
lds with boundary - Patrick Orson\, MPI Bonn
DTSTART;TZID=Europe/London:20220525T160000
DTEND;TZID=Europe/London:20220525T170000
UID:TALK172370AThttp://talks.cam.ac.uk
URL:http://talks.cam.ac.uk/talk/index/172370
DESCRIPTION:The mapping class group of a compact\, simply conn
ected\n4-manifold consists of self-diffeomorphisms
(or self-homeomorphisms\, in the topological cate
gory)\, up to isotopy\, with the convention that t
he boundary is fixed pointwise. In both the smooth
and topological categories\, I will describe suff
icient conditions for two automorphisms to be pseu
doisotopic. Pseudoisotopy is weaker than isotopy\,
but in the topological category we are able to us
e this theorem to fully compute the mapping class
group\, extending a result\nof Quinn from the clos
ed manifold case. The proof makes use of Kreck's m
odified surgery theory. This is joint work with Ma
rk Powell.\n
LOCATION:MR13
CONTACT:Ailsa Keating
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