2026年4月30日（木） (= Thursday 30 April 2026)

Speaker: Vladimir Sosnilo (RIKEN iTHEMS)

数学棟209 (= Room 209, Mathematical Institute, Aobayama Campus)

14:00 -- 15:30

Title: Jouanolou's trick in noncommutative geometry

Abstract: For a quasi-projective variety X Jouanolou's trick provides an affine bundle over X whose total space is an affine scheme J_X. This technique is often used to reduce calculations for quasi-projective varieties to affine ones.

For a qcqs algebraic stack X satisfying connective perfect generation we introduce the so-called local weight structure on the derived category D(X) functorial for affine morphisms. Using this structure we construct a finite resolution of the derived category by categories of modules over certain connective ring spectra. We use this to deduce the DGM-theorem for algebraic stacks. In the case of X being a quasi-projective variety we make our constructions explicit by showing that pushforwards of vector bundles from J_X generate the heart of this weight structure.

Lunch: Those who join will meet at the entrance of the cafeteria in front of Mathematical Institute at 13:00.

ランチ：参加される方は、数学棟前の学食入口に13:00にお集まりください。

Dinner: 18:30 at an izakaya in the city center. If you wish to join, contact Wataru Kai (e-mail address at the top of this page) by Sunday 26 April.

ディナー：18:30に仙台駅付近の居酒屋にて。参加される方は、4月26日（日）までに甲斐亘（メールアドレスはこのページ上部に）にご連絡ください。