Spherical Roots of Spherical Varieties in Characteristic 2
Barbara Schalke (Erlangen)
What 


When 
Jul 17, 2014 from 03:15 pm to 04:15 pm 
Where  Mainz, 05432 (Hilbertraum) 
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The embeddings of a spherical homogeneous space G/H are classified using
Ginvariant valuations of the function field. These can be seen in a certain
Qvector space where they form a cone. Michel Brion proved that in
characteristic zero this is an antidominant fundamental domain for a finite
reflection group generated by the socalled spherical roots of the variety.
This was recently generalized by Friedrich Knop to odd characteristics. After
giving an introduction to the embedding theory I will present interesting
counterexamples in characteristic two.