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Today's seminar
Seminar information archive ～06/08｜Today's seminar 06/09 | Future seminars 06/10～
2026/06/09
Operator Algebra Seminars
16:45-18:15 Room #126 (Graduate School of Math. Sci. Bldg.)
Taisuke Hoshino (Univ. Tokyo)
Rigidity for graph-wreath product II$_1$ factors
[ Reference URL ]
https://www.ms.u-tokyo.ac.jp/~yasuyuki/tokyo-seminar.htm
Taisuke Hoshino (Univ. Tokyo)
Rigidity for graph-wreath product II$_1$ factors
[ Reference URL ]
https://www.ms.u-tokyo.ac.jp/~yasuyuki/tokyo-seminar.htm
Tuesday Seminar on Topology
16:00-17:30 Room #hybrid/056 (Graduate School of Math. Sci. Bldg.)
Pre-registration required. See our seminar webpage.
Masato Tanabe (RIKEN iTHEMS)
Thom polynomials relative to maps prescribed near the boundary (JAPANESE)
https://park.itc.u-tokyo.ac.jp/MSF/topology/TuesdaySeminar/index_e.html
Pre-registration required. See our seminar webpage.
Masato Tanabe (RIKEN iTHEMS)
Thom polynomials relative to maps prescribed near the boundary (JAPANESE)
[ Abstract ]
Thom polynomials are universal cohomological obstructions to the appearance of singularities of given types in differentiable maps. Introduced by R. Thom in the 1950s, they have been extensively studied ever since. In one important line of applications, various invariants of immersions have been expressed in terms of singularities of their extensions (a.k.a. singular Seifert surfaces). However, these formulas are obtained in different forms and remain somewhat scattered.
In this talk, as the first step to unify them, I would like to introduce the notion of Thom polynomials relative to prescribed maps around the boundary. As a main result, we show a structure theorem of Thom polynomials relative to framed immersions. In fact, most of the earlier formulas are summarized as the vanishing of "correction terms" appearing in the structure theorem. Our key tools are Steenrod's obstruction theory and Kervaire's relative characteristic classes, and the K-invariance of singularity types plays an important role.
[ Reference URL ]Thom polynomials are universal cohomological obstructions to the appearance of singularities of given types in differentiable maps. Introduced by R. Thom in the 1950s, they have been extensively studied ever since. In one important line of applications, various invariants of immersions have been expressed in terms of singularities of their extensions (a.k.a. singular Seifert surfaces). However, these formulas are obtained in different forms and remain somewhat scattered.
In this talk, as the first step to unify them, I would like to introduce the notion of Thom polynomials relative to prescribed maps around the boundary. As a main result, we show a structure theorem of Thom polynomials relative to framed immersions. In fact, most of the earlier formulas are summarized as the vanishing of "correction terms" appearing in the structure theorem. Our key tools are Steenrod's obstruction theory and Kervaire's relative characteristic classes, and the K-invariance of singularity types plays an important role.
https://park.itc.u-tokyo.ac.jp/MSF/topology/TuesdaySeminar/index_e.html
