Seminars and Colloquia by Series

Real bordered Floer homology

Series
Geometry Topology Seminar
Time
Monday, April 13, 2026 - 14:00 for 1 hour (actually 50 minutes)
Location
Skiles 006
Speaker
Robert Lipshitz – University of Oregon –

Real Heegaard Floer homology is a new invariant of branched double covers, introduced by Gary Guth and Ciprian Manolescu, and inspired by work of Jiakai Li and others in Seiberg-Witten theory. After sketching their construction, we will describe an extension of the "hat" variant to 3-manifolds with boundary, and the algorithm this gives to compute it when the fixed set is connected. We will end with some open questions.

Cornered skein lasagna theory

Series
Geometry Topology Seminar
Time
Monday, February 2, 2026 - 14:00 for 1 hour (actually 50 minutes)
Location
Skiles 006
Speaker
Yangxiao Luo – University of Virginia –

The Khovanov-Rozansky skein lasagna module was introduced by Morrison-Walker-Wedrich as an invariant of 4-manifold with a framed oriented link in the boundary. I will discuss an extension of the skein lasagna theory to 4-manifolds with codimension 2 corners, and its behavior under gluing. I will also talk about a categorical framework for computing skein lasagna modules of closed 4-manifolds via trisection, as well as an extended 4d TQFT based on skein lasagna theory. This is joint work with Sarah Blackwell and Slava Krushkal.

 

Surgeries on knots and tight contact structures

Series
Geometry Topology Seminar
Time
Monday, December 1, 2025 - 14:00 for 1 hour (actually 50 minutes)
Location
Skiles 006
Speaker
Shunyu Wan – Georgia Tech –

The existence and nonexistence of tight contact structures on the 3-manifold are interesting and important topics studied over the past thirty years. Etnyre-Honda found the first example of a 3-manifold that does not admit tight contact structure, and later Lisca-Stipsicz extended their result and showed that a Seifert fiber space admits a tight contact structure if and only if it is not the smooth (2n − 1)-surgery along the T(2,2n+1) torus knot for any positive integer n.

Surprisingly, since then no other example of a 3-manifold without tight contact structure has been found. Hence, it is interesting to study if all such manifolds, except those mentioned above, admit a tight contact structure. Towards this goal, I will discuss the joint work with Zhenkun Li and Hugo Zhou about showing any negative surgeries on any knot in S^3 admit a tight contact structure.  

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