Differential Geometry seminars
1 result
December 2026
The string group through shifted geometric quantization
Aditya Dwarkesh· University of Regina, Canada
Aditya Dwarkesh explains how geometric quantization extends from ordinary symplectic geometry to higher stacks represented by simplicial manifolds. Whereas ordinary prequantization produces line bundles, the shifted setting leads to bundle gerbes, higher-categorical analogues of principal bundles. For a compact simple Lie group G, the string group provides an example of a multiplicative bundle gerbe over G and can be understood through prequantization of BG with a 2-shifted symplectic structure. The talk develops this relationship and may include a sketch of a new model for String(G).
Thu, Dec 10 · 10:00 UTC · Online
Recent recordings
12 recorded talksResolving singular Spin(7) spaces links exceptional geometry with gauge-theory vacuum structure. This talk builds torsion-free structures on compact orbifold resolutions from local ALE data encoded by harmonic self-dual forms. It explains the relation to supersymmetric gauge equations and asks when local solutions extend globally. Gluing methods and Dirac operators identify analytic obstructions, with explicit examples attaining full Spin(7) holonomy.
Recorded
Video · 1 h 4 minDifferential EquationsTheoretical PhysicsSeries: Perimeter Institute Recorded Seminar Archive
Quantum algebras from generalized Poisson sigma models
Keyou Zeng· Harvard University
Poisson sigma models connect geometric deformation with quantum field theory. This talk extends them into higher-dimensional theories with holomorphic and topological directions and relates the construction to quantization of factorization algebras. It develops interfaces, boundaries and defects, then uses Koszul duality to connect the models with quantum-group structures, including examples involving Lie bialgebras, W-algebras and Yangians.
Recorded
This talk introduces non-negative Ollivier–Ricci curvature on graphs and examines what it implies for the large-scale geometry of bounded-degree networks. It presents recent results developed jointly with Camillo Brena and Florentin Munch without assuming prior familiarity with this curvature notion.
Recorded
Curvatures of graphs
Fan Chung· UC San Diego
Discrete curvature measures local graph geometry, yet can constrain large-scale behaviour. This talk connects curvature with eigenvalues, eigenvectors, expansion, transport and clustering, illustrating how a local invariant can yield global information about a graph.
Recorded
Video · 1 h 4 min · CaptionsGeometryLinear AlgebraSeries: Simons Institute for the Theory of Computing
A Look at Entropic Ricci Curvature on Weighted Graphs
Supanat Kamtue· Chulalongkorn University
Entropy convexity in Wasserstein space supplies a notion of Ricci curvature for discrete weighted graphs. This talk develops its local interpretation through infinitesimal entropy changes, then applies the framework to specific graph families. Sharper estimates for cycles and abelian Cayley graphs illustrate the resulting improvements.
Recorded
Ollivier and Bakry–Émery curvature can be computed from local graph structure. This talk explains how those notions constrain global diameter and Laplace-spectrum properties, relates the bounds to Riemannian comparison theorems, and considers classification questions for spaces attaining equality.
Recorded