Tuesday Seminar on Topology

Seminar information archive ~10/31Next seminarFuture seminars 11/01~

Date, time & place Tuesday 17:00 - 18:30 056Room #056 (Graduate School of Math. Sci. Bldg.)
Organizer(s) HABIRO Kazuo, KAWAZUMI Nariya, KITAYAMA Takahiro, SAKASAI Takuya

Next seminar

2025/11/04

17:00-18:00   Online
Pre-registration required. See our seminar webpage.
Kazuto Takao (Tohoku University)
Diagrammatic criteria for strong irreducibility of Heegaard splittings and finiteness of Goeritz groups (JAPANESE)
[ Abstract ]
Casson-Gordon gave a criterion for Heegaard splittings of 3-manifolds to be strongly irreducible. By strengthening it, Lustig-Moriah gave a criterion for Goeritz groups of Heegaard splittings to be finite. Their criteria are based on Heegaard diagrams formed by maximal disk systems of the handlebodies. We generalize them for arbitrary disk systems, including minimal ones. As an application, we give Heegaard splittings with non-minimal genera and finite Goeritz groups. This is based on joint work with Yuya Koda.
[ Reference URL ]
https://park.itc.u-tokyo.ac.jp/MSF/topology/TuesdaySeminar/index_e.html