# Algebra/Topology Seminar

### Algebra/Topology Seminar – Bulent Tosun, University of Alabama

228 Gordon Palmer Hall Tuscaloosa, AL, United StatesContact geometry in low dimensions

### Algebra/Topology Seminar – Honghao Gao (Michigan State University)

ZoomTitle: Legendrian invariants, Lagrangian fillings and cluster algebras Abstract: Classifications of Legendrian knots and their exact Lagrangian fillings are central questions in low-dimensional contact and symplectic topology. Recent development suggests that one can use cluster seeds to distinguish exact Lagrangian fillings. It requires a filling-to-cluster functoriality over a moduli space of Legendrian invariants. This invariant

### Algebra/Topology Seminar – JungHwan Park (Georgia Institute of Technology)

ZoomTitle: On rationally slice knots Abstract: A knot in the three-sphere is called slice if it bounds a smooth disk in the four-ball. If one only requires the disk to be in a rational homology four-ball, then we say that the knot is rationally slice. We present a rationally slice knot which is not slice even

### Algebra/Topology Seminar – Marco Trombetti (University of Naples Federico II)

ZoomTitle: Abstract Infinite Group Theory in Linear Groups. Abstract: It is a classical result that the commutator subgroup of a group $G$ is finite whenever such is the factor group $G/Z(G)$. In general, this result cannot be reverted: there are (soluble) groups with a finite commutator subgroup but an infinite factor over the centre. However,

### Algebra/Topology Seminar – Ina Petkova (Dartmouth College)

ZoomTitle: A contact invariant from bordered Heegaard Floer homology Abstract: Given a contact structure on a bordered 3-manifold, we describe an invariant which takes values in the bordered sutured Floer homology of the manifold. This invariant satisfies a nice gluing formula, and recovers the Oszvath-Szabo contact class in Heegaard Floer homology. This is joint work

### Algebra/Topology Seminar – Hakan Doga (University of Buffalo)

ZoomTitle: A combinatorial description of the knot concordance invariant epsilon Abstract: Sitting at the intersection of 4-dimensional topology and knot theory, the knot concordance group is an important object in low-dimensional topology whose structure is not yet fully explored and understood. One approach to study knot concordance is to use knot Floer homology, introduced by

### Algebra/Topology Seminar – Eamonn Tweedy (Widener University)

ZoomTitle: The co-rank of three-dimensional homology handlebody groups Abstract: A group G is called very large if G has a non-abelian free quotient. We examine the question of which three-manifolds have very large fundamental group. This question is especially subtle for a three-dimensional homology handlebody of genus g, since the fundamental group of such a