Current students

We hope you are enjoying your time in our graduate programs. Check out our course offerings, information about degree completion, the PhD qualifying exams, the PhD lecturing requirement, and instructions on submitting your PhD annual activity report. If you still have some years ahead in your grad studies, you might be interested in applying for scholarships.

If you have any administrative questions, please contact us at cograd@uwaterloo.ca.

Seminars in Combinatorics and Optimization

Friday, June 14, 2024 3:30 pm - 4:30 pm EDT (GMT -04:00)

Tutte Colloquium - Chaitanya Swamy

Title: Stochastic Minimum Norm Combinatorial Optimization

Speaker: Chaitanya Swamy
Affiliation: University of Waterloo
Location: MC 5501

Abstract: We develop a framework for designing approximation algorithms for a wide class of (1-stage) stochastic-optimization problems with norm-based objective functions. We introduce the model of stochastic minimum-norm combinatorial optimization, wherein the costs involved are random variables with given distributions, and we are given a monotone, symmetric norm f. Each feasible solution induces a random multidimensional cost vector whose entries are independent random variables, and the goal is to find a solution that minimizes the expected f-norm of the induced cost vector. This is a very rich class of objectives, containing all l_p norms, as also Top-l norms (sum of l largest coordinates in absolute value), which enjoys various closure properties.

Monday, June 17, 2024 11:30 am - 12:30 pm EDT (GMT -04:00)

Algebraic Graph Theory - Julianna Tymoczko

Title: Webs and quantum representations

Speaker: Julianna Tymoczko
Affiliation: Smith College
Location: Please email Sabrina Lato for Zoom link.

Abstract: A web is a directed, labeled plane graph satisfying certain conditions coming from representation theory. Each web corresponds to a specific invariant vector in a tensor product of fundamental representations of a quantum group. In this talk, we introduce a process called stranding, which encodes as the monomial terms in a web’s associated vector as a collection of paths in the web graph.  We also describe how the strandings connect seemingly-unrelated ideas in combinatorics (e.g. noncrossing matchings) and geometry (e.g. certain algebraic varieties called Springer fibers).

Tuesday, June 18, 2024 3:00 pm - 4:00 pm EDT (GMT -04:00)

Graphs and Matroids Seminar - Thomas Lesgourgues

Title: Ramsey with purple edges

Speaker: Thomas Lesgourgues
Affiliation: University of Waterloo
Location: MC 5479

Abstract: Motivated by a question of David Angell, we study a variant of Ramsey numbers where some edges are coloured with both red and blue colours, (i.e. are called ‘purple’ edges). Specifically, we are interested in the largest number g = g(s, t, n), for some s and t and n < R(s, t), such that there exists a red-blue-purple colouring of Kn with g purple edges, without a red-purple Ks and without a blue-purple Kt. We determine g asymptotically for a large family of parameters. The talk will be introductory in nature. Since the concept of double-coloured edges is new in this context, there is a plethora of open questions. Joint work with Anita Liebenau and Nye Taylor.