Text only print
Full screen print
Colloquium
Seminar information archive ～10/22｜Next seminar｜Future seminars 10/23～
| Organizer(s) | AIDA Shigeki (chair), IKE Yuichi, IMAI Naoki, HAYASHI Shuhei |
|---|---|
| URL | https://www.ms.u-tokyo.ac.jp/seminar/colloquium_e/index_e.html |
2026/11/27
15:30-16:30 Room #NISSAY Lecture Hall (Graduate School of Math. Sci. Bldg.)
Yuichiro Tanaka (Graduate School of Mathematical Sciences, The University of Tokyo)
Visible actions of real reductive groups and multiplicity-free representations (日本語)
Yuichiro Tanaka (Graduate School of Mathematical Sciences, The University of Tokyo)
Visible actions of real reductive groups and multiplicity-free representations (日本語)
[ Abstract ]
A unitary representation of a locally compact group is multiplicity-free if each irreducible representation appears at most once in its irreducible decomposition.
With the aim of a unified framework for multiplicity-free representations of Lie groups, T. Kobayashi introduced the notion of visible action for holomorphic group-actions. Kobayashi's propagation theorem for the multiplicity-freeness property provides a uniform explanation for the multiplicity-freeness of various kinds of representations that had previously been treated individually.
Furthermore, it has led to the discovery of new multiplicity-free theorems beyond those previously known. In this talk, I will present some basic results on visible actions and discuss several recent developments.
A unitary representation of a locally compact group is multiplicity-free if each irreducible representation appears at most once in its irreducible decomposition.
With the aim of a unified framework for multiplicity-free representations of Lie groups, T. Kobayashi introduced the notion of visible action for holomorphic group-actions. Kobayashi's propagation theorem for the multiplicity-freeness property provides a uniform explanation for the multiplicity-freeness of various kinds of representations that had previously been treated individually.
Furthermore, it has led to the discovery of new multiplicity-free theorems beyond those previously known. In this talk, I will present some basic results on visible actions and discuss several recent developments.
