Contact Info
Combinatorics & Optimization
University of Waterloo
Waterloo, Ontario
Canada N2L 3G1
Phone: 519-888-4567, ext 33038
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Monday, September 25, 2023 11:30 AM EDT
Title: Quantum symmetries of Hadamard matrices
| Speaker: | Daniel Gromada |
| Affiliation: | Czech Technical University in Prague |
| Location: | Please contact Sabrina Lato for Zoom link |
Abstract: The main purpose of this talk is to explain the idea behind the main results of a recent article arXiv:2210.02047 about quantum symmetries of Hadamard matrices. First, we recall the notion of quantum symmetries from the viewpoint of quantum groups as well as diagrammatic categories. On the example of a finite (quantum) space, we show, how the diagrammatic approach can be used to prove that all finite spaces (of size at least four) have quantum symmetries and all finite quantum spaces of a given size are mutually quantum isomorphic. The same technique is used to show analogous results for Hadamard matrices. Finally, we would like to list a couple of questions and research suggestions related to this topic.
Thursday, September 28, 2023 2:00 PM EDT
Title: Closure of Deodhar components
| Speaker: | Kartik Singh |
| Affiliation: | University of Waterloo |
| Location: | MC 6029 |
There will be a pre-seminar presenting relevant background at the beginning graduate level starting at 1pm.
Abstract: Deodhar decomposition of the Grassmannian is finest decomposition (that we know of) for which the components are homeomorphic to affine spaces. So, it's natural to be interested in their topology. In the talk we will try to describe a combinatorial rule that can possibly describe the closure of Deodhar decomposition. This work is joint with Olya Mandelshtam and Kevin Purbhoo.
Thursday, September 28, 2023 3:00 PM EDT
Title: Structure in minor-closed classes of matroids
| Speaker: | Jim Geelen |
| Affiliation: | University of Waterloo |
| Location: | MC 5417 |
Abstract: I will give a brief overview of the structure of matroids in minor-closed classes representable over a fixed finite field. Then I will discuss open problems related to extending those results to more general minor-closed classes of matroids.