代数幾何学セミナー

過去の記録 ~04/30次回の予定今後の予定 05/01~

開催情報 金曜日 13:30~15:00 数理科学研究科棟(駒場) ハイブリッド開催/117号室
担当者 權業 善範、中村 勇哉、田中 公

2023年04月28日(金)

13:30-15:00   数理科学研究科棟(駒場) ハイブリッド開催/117号室
吉野太郎 氏 (東大数理)
On the degree of irrationality of complete intersections (Japanese )
[ 講演概要 ]
The degree of irrationality of a variety X is the minimum degree of a dominant, generically finite rational map from X to a rational variety. This invariant gives a measure of how far X is from being rational. There were some varieties whose degree of irrationality was computed. For example, in 2017, Bastianelli, De Poi, Ein, Lazarsfeld, and Ullery computed the degree of irrationality of very general hypersurfaces of general type by using the positivity of the canonical line bundle. On the other hand, in 2020, Chen and Stapleton obtained the lower bound of the degree of irrationality of very general Fano hypersurfaces by using the reduction of modulo p.
In this talk, we will show that we can obtain the lower bound of the degree of irrationality of very general Fano complete intersections. For obtaining the bound, we make a minor adjustment to Chen--Stapleton's method using the trace map of differential modules.
This talk is based on joint work with Lucas Braune.