Thursday, April 30, 2020

2020-05-07 / 10:00 ~ 11:40

콜로퀴엄 - 위상수학 세미나: Knots, surfaces, and 3- and 4-manifolds

by 박정환(Georgia Institute of Technology)

There are two different but closely related perspectives in low dimensional topology. Both are motivated by the fact that it is often easier to understand manifolds when broken into smaller pieces. Given a closed 3-manifold, it is natural to ask which compact 4-manifolds can it bound. More concretely, one can ask whether it bounds a compact 4-manifold with simple homology. I will talk about some recent developments in this direction including joint work with Aceto and Celoria. Another perspective is to consider knots in a 3-manifold which arises as the boundary of a 4-manifold and ask what kind of surfaces can the knots bound in the 4-manifold. A commonly studied special case is the 3-sphere and the 4-ball. I will talk about a result joint with Hom and Kang where we study the complexity of disks embedded in the 4-ball.

2020-05-06 / 16:00 ~ 17:30

학과 세미나/콜로퀴엄 - 위상수학 세미나: On Translation Lengths of Anosov Maps on Curve Graph of Torus

by Changsub Kim(KAIST)

We show that an Anosov map has a geodesic axis on the curve graph of a torus. The direct corollary of our result is the stable translation length of an Anosov map on the curve graph is always a positive integer. As the proof is constructive, we also provide an algorithm to calculate the exact translation length for any given Anosov map.

Events for the 취소된 행사 포함