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SUMMARY:Mapping class groups for simply connected 4-manifolds with boundar
 y - Patrick Orson\, MPI Bonn
DTSTART:20220525T150000Z
DTEND:20220525T160000Z
UID:TALK172370@talks.cam.ac.uk
CONTACT:Ailsa Keating
DESCRIPTION:The mapping class group of a compact\, simply connected\n4-man
 ifold consists of self-diffeomorphisms (or self-homeomorphisms\, in the to
 pological category)\, up to isotopy\, with the convention that the boundar
 y is fixed pointwise. In both the smooth and topological categories\, I wi
 ll describe sufficient conditions for two automorphisms to be pseudoisotop
 ic. Pseudoisotopy is weaker than isotopy\, but in the topological category
  we are able to use this theorem to fully compute the mapping class group\
 , extending a result\nof Quinn from the closed manifold case. The proof ma
 kes use of Kreck's modified surgery theory. This is joint work with Mark P
 owell.\n
LOCATION:MR13
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