Contact Info
Combinatorics & Optimization
University of Waterloo
Waterloo, Ontario
Canada N2L 3G1
Phone: 519-888-4567, ext 33038
PDF files require Adobe Acrobat Reader.
Thursday, March 29, 2018 3:30 PM EDT
Title: Knots and their (embedded) graphs
| Speaker: | Iain Moffatt |
| Affiliation: | Royal Holloway University of London |
| Room: | MC 5479 |
Abstract:
There is a classical and well-known way to describe an alternating knot or link as a plane graph, known as its Tait graph.
Wednesday, March 28, 2018 4:00 PM EDT
Title: Tractable Approximations to Robust Conic Optimization Problems (paper by D. Bertsimas, M. Sim)
| Speaker: | Matthew William Slavin |
| Affiliation: | University of Waterloo |
| Room: | MC 5479 |
Abstract: We review the paper listed in the title of this talk. In the paper, Bertsimas and Sim propose a relaxed robust counterpart for general conic optimization problems
Tuesday, March 27, 2018 4:00 PM EDT
Title: Implementing cryptography at scale
| Speaker: | Edward Knapp |
| Affiliation: | |
| Room: | MC 5501 |
Abstract: Many cryptographic primitives have rough edges which make them difficult to use properly (by both experts and non-experts).
Monday, March 26, 2018 1:00 PM EDT
Title: LWE Part 2: A quantum discrete Gaussian sampler.
| Speaker: | Luis Ruiz |
| Affiliation: | University of Waterloo |
| Room: | MC 6486 |
Abstract: In this talk we will describe how a (quantum) Gaussian sampler could be constructed if we had access to a solver of a decoding problem.
Friday, March 23, 2018 3:30 PM EDT
Title: Morphisms of complex Hadamard matrices
| Speaker: | Padraig O Cathain |
| Affiliation: | Worcester Polytechnic University |
| Room: | MC 5501 |
Abstract:
Let M be a matrix with complex entries of unit norm. A well-known theorem of Hadamard bounds the magnitude of the determinant of M as a function of its dimension, and M is a complex Hadamard matrix if M meets Hadamard's bound with equality.
Thursday, March 22, 2018 3:30 PM EDT
Title: Excluding claws in binary matroids
| Speaker: | Kazuhiro Nomoto |
| Affiliation: | University of Waterloo |
| Room: | MC 5479 |
Abstract: A simple binary matroid is claw-free if no rank-3 flats are independent. We discuss an exact structure theorem for such matroids and sketch its proof. This is joint work with Peter Nelson.
Thursday, March 22, 2018 1:30 PM EDT
Title: Unitary groups over finite fields
| Speaker: | Chris Godsil |
| Affiliation: | University of Waterloo |
| Room: | MC 6486 |
Abstract: I will discuss the unitary groups over finite fields, and the structures on which they act (these include 2-designs and generalized quadrangles).
Wednesday, March 21, 2018 4:00 PM EDT
Title: D. Bertsimas, I. Popescu - Optimal inequalities in probability theory: A convex optimization approach
| Speaker: | Ashkay Ramachandran |
| Affiliation: | University of Waterloo |
| Room: | MC 5479 |
Abstract: Abstract. We propose a semidefinite optimization approach to the problem of deriving tight moment
Friday, March 16, 2018 3:30 PM EDT
Title: A George Szekeres formula for restricted partitions
| Speaker: | Bruce Richmond |
| Affiliation: | University of Waterloo |
| Room: | MC 5501 |
Abstract:
We give asymptotic formulas for the number of integer partitions of n with at most j parts and having largest part at most r, say A(n,j,r). We do this also for the number of partitions of n with largest part equal to r and having exactly j parts, say C(n,j,r).
Thursday, March 15, 2018 1:30 PM EDT
Title: Quantum State Transfer
| Speaker: | Christopher van Bommel |
| Affilliation: | University of Waterloo |
| Room: | MC 6486 |
Abstract:
Many quantum algorithms may be modeled as a quantum process occurring on a graph. We interpret quantum channels implemented by spin chains as wires for transmission of states.
Wednesday, March 14, 2018 4:00 PM EDT
Title: Data-driven Inverse Optimization with Imperfect Information
| Speaker: | Stefan Sremac |
| Affilliation: | University of Waterloo |
| Room: | MC 5479 |
Abstract:
We continue our reading group with a paper by Kuhn et al with the same title as above.
Tuesday, March 13, 2018 4:30 PM EDT
Title: What's an amplituhedron?
| Speaker: | Cameron Marcott |
| Affilliation: | University of Waterloo |
| Room: | MC 5501 |
Abstract:
I'll introduce the amplituhedron, focusing on why the suffix "hedron" is justified.
Monday, March 12, 2018 1:30 PM EDT
Title: LWE Part 1: The problem, the cryptosystem and its relationship to lattice Problems
| Speaker: | Luiz Ruiz |
| Affiliation: | University of Waterloo |
| Room: | MC 6486 |
Abstract:
In this talk we will give an overview of the Learning With Errors problem,
Friday, March 9, 2018 3:30 PM EST
Title: Chromatic Symmetric Functions and H-Free Graphs
| Speaker: | Angèle Hamel |
| Affiliation: | Wilfrid Laurier University |
| Room: | MC 2038 (not 5501) |
Abstract:
Chromatic symmetric functions are defined in terms of colourings of particular graphs. Some key conjectures in this area concern whether chromatic symmetric functions of claw-free graphs can be written in terms of other symmetric functions with positive coefficients.
Thursday, March 8, 2018 3:30 PM EST
Title: Claws, ω and χ: induced binary submatroids
| Speaker: | Peter Nelson |
| Affilliation: | University of Waterloo |
| Room: | MC 5479 |
Abstract:
I will discuss the interplay between clique number, chromatic number, and excluding induced submatroids in the setting of binary matroids.
Thursday, March 8, 2018 1:30 PM EST
Title: Unitary Groups, II
| Speaker: | Chris Godsil |
| Affiliation: | University of Waterloo |
| Room: | MC 6486 |
Abstract:
Actually the title should be 2 Unitary groups - I will discuss the 2-dimensional unitary groups.
Monday, March 5, 2018 3:30 PM EST
Title: Traveling Salesman Problems
| Speaker: | William (Bill) Cook |
| Affiliation: | University of Waterloo |
| Room: | MC 5417 |
Abstract:
We discuss open research questions, both theoretical and computational, surrounding the traveling salesman problem.
Thursday, March 1, 2018 3:30 PM EST
Title: Counting matroids
| Speaker: | Jorn van der Pol |
| Affiliation: | University of Waterloo |
| Room: | MC 5479 |
Abstract:
We discuss several recent results concerning matroid enumeration and typical properties of matroids, emphasizing the central role that sparse paving matroids play in these results.
Thursday, March 1, 2018 1:30 PM EST
Title: Unitary Groups
| Speaker: | Chris Godsil |
| Affiliation: | University of Waterloo |
| Room: | MC 6486 |
Abstract:
Unitary groups play an important role in physics and in finite geometry. This talk, the first of two, will provide an introduction to the topic focusing on the case where the underlying field is the complex numbers.