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Please note: The University of Waterloo is closed for all events until further notice.

Welcome to Combinatorics and Optimization

The C&O department has 33 faculty members and 60 graduate students. We are intensely research oriented and hold a strong international reputation in each of our six major areas:

Read more about the department's research to learn of our contributions to the world of mathematics!

Tutte's Distinguished Lecture Series 

The very successful Tutte's 100th Distinguished Lecture Series has now completed. That success has led to a Tutte Distinguished Lecture once per term. The next lecture will happen in the Spring term.

*Recordings of occurred talks are all available on C&O's YouTube Channel   

Grad Studies: Fall 2020 applications now open

 New Deadline: February 1, '20

  1. May 21, 2021Stephen Melczer's book on Analytic Combinatorics has been published
    Melczer book

    "An Invitation to Analytic Combinatorics: From One to Several Variables", written by C&O professor Stephen Melczer, has been published by Springer.

  2. May 20, 2021Spring 2021 convocation
    Convocation Spring 2021

    Three Ph.D. and seven M.Math. C&O students will receive their degrees at the Spring 2021 convocation on June 18.

  3. May 5, 2021C&O welcomes its two newest faculty members
    Tutte square

    Olya Mandelshtam and Kanstantsin Pashkovich are the newest faculty members in the C&O department.

Read all news
  1. June 18, 2021Algebraic Graph Theory Seminar - Dheer Noal Desai

    Title: The spectral radius of graphs with no odd wheels

    Speaker: Dheer Noal Desai
    Affiliation: University of Delaware
    Zoom: Contact Soffia Arnadottir


    The odd wheel W_{2k+1} is the graph formed by joining a vertex to a cycle of length 2k. In this talk, we will investigate the largest value of the spectral radius of the adjacency matrix of an n-vertex graph that does not contain W_{2k+1}.

  2. June 18, 2021Tutte Colloquium - Marni Mishna

    Title: Lattice Walk Enumeration: Analytic, algebraic and geometric aspects

    Speaker: Marni Mishna 
    Affliliation: Simon Fraser University
    Zoom: Contact Emma Watson


    This talk will examine the rich topic of lattice path enumeration. A very classic object of combinatorics, lattice walks withstand study from a variety of perspectives. Even the simple task of classifying the two dimensional walks restricted to the first quadrant has brought into play a surprising diversity of techniques from algebra to analysis to geometry. We will consider walks under a few different lenses.

  3. June 21, 2021Algebraic Graph Theory Seminar - Paula Kimmerling

    Title: Average Mixing Matrices of Trees and Stars

    Speaker: Paula Kimmerling
    Affiliation: Washington State University
    Zoom: Contact Soffia Arnadottir


    We define the average mixing matrix (AMM) of a continuous-time quantum walk on a graph using the orthogonal projections onto the eigenspaces of the adjacency matrix A. From there, one of the properties that has been studied is the rank of the AMM. This is easiest to do if the eigenvalues of A are simple, and we’ll review some of the results on this from Coutinho et. al. (2018).

All upcoming events