skip to content
 

Extensions of Grothendieck's theorem on principal bundles over the projective line

Presented by: 
M Thaddeus [Columbia]
Date: 
Tuesday 21st June 2011 - 11:30 to 12:30
Venue: 
INI Seminar Room 2
Abstract: 
Let G be a split reductive group over a field. Grothendieck and Harder proved that any principal G-bundle over the projective line reduces (essentially uniquely) to a maximal torus. In joint work with Johan Martens, 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 these, or the stack-theoretic quotient of any of these by a torus action.
The video for this talk should appear here if JavaScript is enabled.
If it doesn't, something may have gone wrong with our embedded player.
We'll get it fixed as soon as possible.
University of Cambridge Research Councils UK
    Clay Mathematics Institute The Leverhulme Trust London Mathematical Society Microsoft Research NM Rothschild and Sons