代数学コロキウム

過去の記録 ~07/20次回の予定今後の予定 07/21~

開催情報 水曜日 17:00~18:00 数理科学研究科棟(駒場) 117号室
担当者 今井 直毅,ケリー シェーン

2023年05月31日(水)

17:00-18:00   数理科学研究科棟(駒場) 117号室
竹内大智 氏 (理化学研究所)
Quadratic $\ell$-adic sheaf and its Heisenberg group (日本語)
[ 講演概要 ]
Quadratic Gauss sums are usually defined only for finite fields of odd characteristic. However, it is known that there is a reformulation in which one can uniformly treat the case of even characteristic. In this talk, I will introduce a new class of $\ell$-adic sheaf, which I call quadratic sheaf. This is a sheaf-theoretic enhancement of the reformulation of quadratic Gauss sum, in the sense of the function-sheaf dictionary. After explaining its cohomological properties and consequences, such as a version of Hasse-Davenport relation, I will show that a certain finite Heisenberg group naturally acts on a quadratic sheaf. I will also report various results that can be deduced from this action.