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New York Group Theory Seminar: Friday, September 18, 2026, 4:15pm, room 6417, CUNY Graduate Center
Speaker: Jennifer Taback (Bowdoin College)
Title: An overview of medium-scale Ricci curvature for discrete groups
Abstract:
Bar-Natan, Duchin, and Kropholler introduced medium-scale Ricci curvature as a discrete curvature for Cayley graphs of finitely generated groups, computed at varying scales to capture different aspects of the geometry. In the first half of the talk I will motivate this definition and relate it to some standard properties studied in geometric group theory. I will then describe the unusual behavior of this curvature in Thompson's group F with respect to the standard finite generating set. Like the discrete Heisenberg group, F contains a positive density of elements of positive curvature, of negative curvature, and of zero curvature at any scale. Additionally, for each of the three possible signs, every isomorphism class of subgroups of F contains countably many representatives in which all nontrivial elements have curvature of that sign, at any scale. This is joint work with Sean Cleary.
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New York Group Theory Seminar: Friday, September 25, 2026, 4:15pm, room 6417, CUNY Graduate Center
Speaker: Ilya Kapovich (Hunter College and CUNY Graduate Center)
Title:
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New York Group Theory Seminar: Friday, October 2, 2026, 4:15pm, room 6417, CUNY Graduate Center
Speaker: Jayadev Athreya (Fordham University)
Title:
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New York Group Theory Seminar: Friday, October 9, 2026, 4:15pm, room 6417, CUNY Graduate Center
Speaker: Yukun Du (University of Georgia)
Title:
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New York Group Theory Seminar: Friday, December 4, 2026, 4:15pm, room 6417, CUNY Graduate Center
Speaker: David Fisher (Rice University) [to be confirmed]
Title:
Abstract:
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