# Regensburg low-dimensional geometry and topology seminar

The seminar takes place on Zoom (see information below) every Tuesday at 16:00 CET (that is 7am on the US west coast, 10am on the US east coast, 10pm in China and 11pm in Korea and Japan).

Talks are split into a 40 minute and a 20 minute part, with a 15 minute tea break in between (you have to brew your own tea).

## Upcoming Talks

Date Speaker Title Abstract
June 16 Gordana Matic (Univ. of Georgia/MPIM Bonn) Spectral order invariant and obstruction to Stein fillability In this joint work with Ca\ugatay Kutluhan, Jeremy Van Horn- Morris and Andy Wand, we define an invariant of contact structures in dimension three arising from introducing a filtration on the boundary operator in Heegaard Floer homology. This invariant takes values in the set $\Z_{\geq0}\cup\{\infty\}$. It is zero for overtwisted contact structures, $\infty$ for Stein fillable contact structures, non-decreasing under Legendrian surgery, and computable from any supporting open book decomposition. I will give the definition and discuss computability of the invariant. As an application, we give an easily computable obstruction to Stein fillability on closed contact 3-manifolds with non-vanishing Ozsvá th-Szabó contact class.
June 23 Lisa Piccirillo (MIT) tba tba
June 30 Kathryn Mann (Cornell) tba tba
July 7 Mikhail Khovanov (Columbia University) Introduction to foam evaluation and its uses tba
July 14 Claudius Zibrowius (UBC Vancouver) tba tba
July 21 Marc Lackenby (University of Oxford) tba tba

## Zoom information

Zoom Meeting ID: 924 2829 6353

The password is the answer to the following riddle (lower case, singular, no article): As a topologist, what do you typically glue together from charts? (Hint: It's not an orbifold).

We encourage you to enable your video, for a more interactive atmosphere. The talks are recorded and made available on this webpage, including audio and video of questions from the audience.