Contact Info
Combinatorics & Optimization
University of Waterloo
Waterloo, Ontario
Canada N2L 3G1
Phone: 519-888-4567, ext 33038
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Thursday, December 12, 2019 3:00 PM EST
Title: OutFn, M_gn and renormalized topological field theory
| Speaker: | Michael Borinsky |
| Affiliation: | Nikhef |
| Room: | MC 5417 |
Abstract:
I will report on recent joint work with Karen Vogtmann on the Euler characteristic of Out(F_n) and the moduli space of graphs.
Thursday, December 12, 2019 1:00 PM EST
Title: Graph covers with two new eigenvalues
| Speaker: | Olha Silina |
| Affiliation: | University of Waterloo |
| Room: | MC 5479 |
Abstract:
I am going to talk about graph covers. If $Y$ is a cyclic cover of $X$, it turns out that $Y$ has the same spectrum as $X$ plus (possibly) some new eigenvalues.
Friday, December 6, 2019 3:03 PM EST
Title: Biometric security: Design, implementation, and challenges
| Speaker: | Koray Karabina |
| Affiliation: | Florida Atlantic University |
| Room: | MC 5501 |
Abstract:
Biometric based cybersecurity technologies offer significant advantages in authentication, identification, and access control mechanisms.
Thursday, December 5, 2019 3:00 PM EST
Title: Inverses of Trees
| Speaker: | Krystal Guo |
| Affiliation: | Centre de Recherches Mathématiques & Université de Montréal |
| Room: | MC 5417 |
Abstract:
A tree is invertible if and only if it has a perfect matching.
Godsil considers an invertible tree T and finds that the inverse of the adjacency matrix has entries in {0, ±1} and is the signed adjacency matrix of a graph which contains T.
Thursday, December 5, 2019 9:30 AM EST
Title: How can we optimize nonsmooth objectives globally?
| Speaker: | Andreas Griewank |
| Affiliation: | Humboldt University, Germany |
| Room: | MC 5501 |
Abstract:
In machine learning objective functions that are only piecewise smooth and should be globally minimized abound. The standard method of dealing with them is to apply a stochastic gradient method disregarding the rare points of nonsmoothness and hoping for the best as far as global optimality of the computed solution is concerned.