##### Department of Mathematics,

University of California San Diego

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### Math 292 - Topology Seminar

## Hannah Schwartz

#### Princeton University

## Isotopy vs. homotopy for disks with a common dual

##### Abstract:

Recent work of both Gabai and Schneiderman-Teichner on the smooth isotopy of homotopic surfaces with a common dual has reinvigorated the study of concordance invariants defined by Freedman and Quinn in the 90's, along with homotopy theoretic invariants of Dax from the 70's obstructing isotopy of disks. Using the Dax invariant, we will give conditions under which pairs of homotopic properly embedded disks in a smooth 4-manifold with boundary with a common dual are isotopic.

Host: Jianfeng Lin

### November 10, 2020

### 10:30 AM

### Zoom information: Meeting ID: 933 6734 4286 Password: topology

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