Seminar by Laura Marino at UniTS + dinner

[ZUDDAS DANIELE]

Dear all,

tomorrow Wednesday 12 November at 16:15 we will have a talk by Dr Laura Marino (University of Hamburg). Please notice the uncommon room and time.

Title: A topological application of Khovanov homology
Abstract: The Gordian distance u(K,K′) between two knots K and K′ is the minimal number of crossing changes needed to relate K and K′. The unknotting number u(K) of a knot K arises as the Gordian distance between K and the trivial knot. Rasmussen was the first to find a connection between Khovanov homology and u: his invariant s, extracted from Khovanov homology, yields a lower bound for the slice genus and, as a consequence, for u(K). In this talk, after introducing Khovanov homology and the s invariant, I will describe a new invariant λ, extracted from a universal version of Khovanov homology. Although it is not connected to the slice genus, λ is a lower bound for u, and in fact the inequality |s(K)| ≤ 2λ(K) always holds. Moreover, λ displays relations to a generalization of u, the proper rational Gordian distance. This is joint work with L. Lewark and C. Zibrowius.

Venue: Room 5B, 5th floor of building H2bis, UniTS, Via Valerio 12/1.

On the evening we will have a dinner with the speaker, in case just let me know as soon as possible if you want to join.

Interested people are cordially invited.

All the best,
Daniele