Uploaded April 2024 | Updated September 2026, 2 weeks ago
Speaker: Alfonso Garmendia (I’Institut d’Estudis Catalans, Barcelona)
Abstract: Principal bundles are essential objects in gauge theories. A basic example of a principal bundle is the frames (or pointwise ordered basis) of a vector bundle on a manifold. Using this principal bundle one can relate geometric connections, reduction and different structures on the underlying manifold. In this talk, we explore properties of some special principal bundle. This is the set of some frames on the tangent vector bundle TG, where G is not only a manifold, but the space of arrows of a Lie groupoid, i.e. TG is a (vector bundle or) VB groupoid. This principal bundle will also be a PB groupoid.
Speaker: Alfonso Garmendia (I’Institut d’Estudis Catalans, Barcelona)
Abstract: Principal bundles are essential objects in gauge theories. A basic example of a principal bundle is the frames (or pointwise ordered basis) of a vector bundle on a manifold. Using this principal bundle one can relate geometric connections, reduction and different structures on the underlying manifold. In this talk, we explore properties of some special principal bundle. This is the set of some frames on the tangent vector bundle TG, where G is not only a manifold, but the space of arrows of a Lie groupoid, i.e. TG is a (vector bundle or) VB groupoid. This principal bundle will also be a PB groupoid.



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![STP Board Meeting Talks - 5 December 2025
Speaker: Dmitry Noshchenko
Title: ceff as a new invariant of 3-manifolds
Abstract: This talk reports on a recent progress towards understanding new structures in low-dimensional topology inspired by physics. Namely, we introduce and study numerical quantity ceff for a closed, oriented 3-manifold M. This has a physical interpretation as a rate of growth of supersymmetric states in gauge theory T[M] corresponding to M. We test several conjectures related to T[M] and ceff for a class of integer homology 3-spheres. Based on arXiv:2508.10087. STP Board Meeting Talks - 5 December 2025](https://i.ytimg.com/vi/9QO8t-cZj7U/mqdefault.jpg)




