Claspers, graspers, barbells | Vidéo | Carmin.tv

00:00:00 / 00:00:00

Claspers, graspers, barbells

By Danica Kosanovic

Appears in collection : Jean Morlet Chair - Trisections and related topics / Chaire Jean Morlet - Trisections et interactions

Infinite lists of non-isotopic and independent diffeomorphisms of S^1 x S^3 have been constructed by Budney and Gabai using barbells, and by Watanabe using claspers. In this talk I will explain how barbells can be obtained from families of dancing circles, called graspers. This perspective is powerful in certain settings, where it provides quick proofs of existence of infinite subgroups of mapping class groups.

Information about the video

Date of recording 16/10/2025
Date of publication 30/10/2025
Institution CIRM
Licence CC BY NC ND
Language English
Audience Researchers, Graduate Students
Director(s) Guillaume Hennenfent
Format MP4

Citation data

DOI 10.24350/CIRM.V.20395303
Cite this video Kosanovic, Danica (16/10/2025). Claspers, graspers, barbells. CIRM. Audiovisual resource. DOI: 10.24350/CIRM.V.20395303
URL https://dx.doi.org/10.24350/CIRM.V.20395303

Domain(s)

Geometric Topology

Bibliography

KOSANOVIĆ, Danica. Diffeomorphisms of 4‐manifolds from graspers. Proceedings of the London Mathematical Society, 2025, vol. 131, no 1, p. e70065. - https://doi.org/10.1112/plms.70065
FERNÁNDEZ, Eduardo, GAY, David T., HARTMAN, Daniel, et al. Grasper families of spheres in $ S^ 2\times D^ 2$ and barbell diffeomorphisms of $ S^ 1\times S^ 2\times I$. arXiv preprint arXiv:2412.07467, 2024. - https://doi.org/10.48550/arXiv.2412.07467

MSC codes

Last related questions on MathOverflow

You have to connect your Carmin.tv account with mathoverflow to add question

Ask a question on MathOverflow

Copyright Carmin.tv 2026

Give feedback