Upsilon invariant for graphs and homology cobordism group of homology cylinders

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Akram Alishahi, University of Georgia

In-Person and Online Talk

Zoom Link:听

Upsilon is an invariant of knots defined using knot Floer homology by Ozsv谩th, Szab贸 and Stipsicz. In this talk, we discuss a generalization of their invariant for embedded graphs in rational homology spheres satisfying specific properties. Our construction will use a generalization of Heegaard Floer homology for 鈥済eneralized tangles鈥 called tangle Floer homology. As a result, we get a family of homomorphisms from the homology cobordism group of homology cylinders (over a surface of genus 0), which is an enlargement of the mapping class group defined by Graoufaldis and Levine.