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SUMMARY:Extensions of Grothendieck's theorem on principal bundles over the
  projective line - Thaddeus\, M (Columbia)
DTSTART:20110621T103000Z
DTEND:20110621T113000Z
UID:TALK31808@talks.cam.ac.uk
CONTACT:Mustapha Amrani
DESCRIPTION:Let G be a split reductive group over a field.  Grothendieck a
 nd Harder proved that any principal G-bundle over the projective line redu
 ces (essentially uniquely) to a maximal torus.  In joint work with Johan M
 artens\, we show that this remains true when the base is a chain of lines\
 , a football\, a chain of footballs\, a finite abelian gerbe over any of t
 hese\, or the stack-theoretic quotient of any of these by a torus action.\
 n
LOCATION:Seminar Room 2\, Newton Institute Gatehouse
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