[K-OS] Knot Online Seminar

[K-OS] is an online research seminar which focuses on knot theory and low-dimensional topology. Talks will be delivered by authors of recent arXiv articles that made a breakthrough in our field. It happens the 3rd Thursday of every month from 16:15 to 17:15 (CET/CEST Berlin, Brussels, Madrid, Paris, Rome, Vienna, Warsaw, Zurich) on Zoom.

It is organized by Alexandra Kjuchukova, Lukas Lewark, Delphine Moussard and Emmanuel Wagner. It benefits from logistical support from the CNRS, the university of Paris and the ETHZ.

If there is a recent arXiv preprint which you would like to see featured on the seminar, please email the organizers with your suggestion.

The K-OS talks are also listed in a Google Calendar.

Forthcoming Talks

17 April 2025

• Speaker: Jae Choon Cha (POSTECH)
• Title: On Calegari’s homotopy 4-spheres (on 2411.10051)
• Abstract: In 2009, in connection with the smooth 4-dimensional Poincaré conjecture, D. Calegari constructed an infinite family of smooth homotopy 4-spheres arising from monodromies of fibered knots in the 3-sphere. We review this construction and prove that all of these are diffeomorphic to the standard 4-sphere. We also discuss some related applications.

15 May 2025

• Speaker: Jingyin Huang (Ohio State)
• Title: Exotic aspherical 4-manifolds (on 2411.19400)
• Abstract: We will explain a construction, which is joint work with Davis, Hayden, Ruberman, and Sunukjian, that gives a pair of closed, aspherical, smooth 4-manifolds that are homeomorphic but not diffeomorphic.