[K-OS] Knot Online Seminar
[K-OS] is an online research seminar which focuses on knot theory and low-dimensional topology. It happens every Thursdays from 14:00 to 15:00 (
CET/CEST Berlin, Brussels, Madrid, Paris, Rome, Vienna, Warsaw, Zurich) on
Zoom.
It is organized by Louis-Hadrien
Robert and Emmanuel
Wagner. It benefits from logistical support from the
CNRS and the university of
Geneva.
13/05/2021
- Speaker: William Ballinger (Princeton University)
- Title: Concordance invariants from Khovanov homology.
- Abstract: The Lee differential and Rasmussen's E(-1)
differential acting on Khovanov homology combine to give
a pair of cancelling differentials, an algebraic
structure that has been studied in the context of knot
Floer homology. I will describe some concordance
invariants that come from this structure, with
applications to nonorientable genus bounds and linear
independence in the concordance group.
20/05/2021
- Speaker: Delphine Moussard (Aix–Marseille Université)
- Title: A triple point knot invariant and the slice and ribbon genera.
- Abstract: The T-genus of a knot is the minimal number
of borromean-type triple points on a normal singular disk
with no clasp bounded by the knot; it is an upper bound
for the slice genus. Kawauchi, Shibuya and Suzuki
characterized the slice knots by the vanishing of their
T-genus. I will explain how this generalizes to provide a
3-dimensional characterization of the slice
genus. Further, I will show that the difference between
the T-genus and the slice genus can be arbitrarily
large. Finally, I will introduce the ribbon counterpart of
the T-genus, which is an upper bound for the ribbon genus,
and we will see that the T-genus and the ribbon T-genus
coincide for all knots if and only if all slice knots are
ribbon.
27/05/2021
- Speaker: Agnès Gadbled (Université Paris–Saclay)
- Title: TBA.
- Abstract: TBA.
03/06/2021
- Speaker: Yuta Nozaki (Hiroshima University)
- Title: TBA.
- Abstract: TBA.
10/06/2021
- Speaker: Raphael Zentner (Universität Regensburg)
- Title: TBA.
- Abstract: TBA.
17/06/2021
- Speaker: Vincent Colin (Université de Nantes)
- Title: TBA.
- Abstract: TBA.
24/06/2021
