May 28 (Wed), 10 am

Zoom https://kimsh.kr/vz

Min, Hyunki (UCLA)

Tight contact structures on small Seifert fibrations

In this talk, I will briefly review the history of tight contact structures on small Seifert fibered spaces. I will introduce a new classification strategy for tight contact structures on Seifert fibered spaces. As an application, we classify tight structures on every surgery of every torus knot in the 3-sphere. As a consequence, we disprove a conjecture of Ghiggini and Van Horn-Morris regarding symplectic fillings of a family of Brieskorn spheres. This is joint work with Etnyre, Tosun, and Varvarezos.

June 2 (Mon), 11 am

KIAS 1423 & Zoom https://kimsh.kr/vz

Alexis Marchand (Kyoto)

Sharp spectral gaps for scl from negative curvature

Stable commutator length is a measure of homological complexity of group elements, with connections to many topics in geometric topology, including quasimorphisms, bounded cohomology, and simplicial volume. The goal of this talk is to shed light on some of its relations with negative curvature. We will present a new geometric proof of a theorem of Heuer on sharp lower bounds for scl in right-angled Artin groups. Our proof relates letter-quasimorphisms (which are analogues of real-valued quasimorphisms with image in free groups) to negatively curved angle structures for surfaces estimating scl.

July 1 (Tue), 11 am

KIAS 8101 & Zoom https://kimsh.kr/vz

Insung Park (Stony Brook)

TBA

TBA

August 5 (Tue), 11 am

KIAS 1423 & Zoom https://kimsh.kr/vz

Ryoo, Seung-Yeon (Caltech)

TBA

TBA