Date: Tuesday, March 10, 2015
Location: 1372 East Hall (2:00 PM to 3:00 PM)
Title: Cylinders in del Pezzo surfaces
Abstract: For a projective variety X and an ample divisor H on it, an Hpolar cylinder in X is an open ruled affine subset whose complement is a support of an effective Qdivisor Qrationally equivalent to H. This notion links together affine, birational and Kahler geometries. I will show how to prove existence and nonexistence of Hpolar cylinders in smooth and mildly singular del Pezzo surfaces (for different polarizations). The obstructions come from log canonical thresholds and Fujita numbers. As an application, 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 Jihun Park (POSTECH) and Joonyeong Won (KAIST).
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Speaker: Ivan Cheltsov
Institution: University of Edinburgh
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