代数幾何学セミナー

過去の記録 ~04/19次回の予定今後の予定 04/20~

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01月31日(火)

14:30-16:00   数理科学研究科棟(駒場) ハイブリッド開催/002号室
いつもと時間が異なります.
Shiji Lyu 氏 (プリンストン大学)
Some properties of splinters via ultrapower (English)
[ 講演概要 ]
A Noetherian (reduced) ring is called a splinter if it is a direct summand of every finite ring extension of it. This notion is related to various interesting notions of singularities, but far less properties are known about splinters.
In this talk, we will discuss the question of "regular ascent"; in the simplest (but already essential) form, we ask, for a Noetherian splinter R, is the polynomial ring R[X] always a splinter. We will see how ultrapower, a construction mainly belonging to model theory, is involved.