Speaker
Prof.
Gavin Brown
Description
Simple flops (the contraction of a single irreducible canonically trivial rational curve on a smooth 3-fold) are in bijection with their Donovan-Wemyss contraction algebras, that is particular noncommutative deformation algebras. We give an intrinsic characterisation of such algebras and classify them, and explain how to recover the flopping curves directly. Joint with Michael Wemyss.