Title Cylinders in Fano varieties
Ivan Cheltsov (Edinburgh)  Seminar Algebraic Geometry (SAG)
What 


When 
Dec 12, 2013 from 10:30 am to 11:30 am 
Where  Bonn, Hörsaal MPI, Vivatsgasse 7 
Contact Name  sachinid 
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A cylinder in a Fano variety is an open ruled affine subset whose complement is a support of an effective anticanonical Qdivisor. This notion links together affine, birational and Kahler geometries. I prove existence and nonexistence of cylinders in smooth and mildly singular (with at most du Val singularities) del Pezzo surfaces. In particular, I will answer an old question of Zaidenberg and Flenner about additive group actions on the cubic Fermat affine threefold cone. This is a joint work with MartinezGarcia, Park and Won.