Welcome to Combinatorics and Optimization

The C&O department has 36 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!



  1. Feb. 15, 2023Sophie Spirkl receives Sloan Foundation Fellowship
    Picture of Sophie Spirkl

    Sophie Spirkl, an assistant professor of Combinatorics and Optimization, has received a prestigious Sloan Research Fellowship from the Alfred P. Sloan Foundation. Spirkl is one of 125 early career researchers in the United States and Canada who received a Fellowship this year.

  2. June 13, 2022Karen Yeats awarded renewed Canada Research Chair
    Karen Yeats

    Karen Yeats, an associate professor in the Department of Combinatorics and Optimization, has recently been named among the latest cohort of Canada Research Chairs.

  3. May 30, 2022Simone Hu wins coveted Governor General’s Gold Medal
    Simone Hu

    A recent graduate of the Department of Combinatorics and Optimization has been awarded this year’s Governor General’s Gold Medal at the master’s level.

    The award is among the most prestigious for students, with only one at the master’s level and one at the PhD level for the entire university.

    Graduate Studies and Postdoctoral Affairs administers the annual award, with each faculty allowed to nominate a single PhD and a single master’s candidate.

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  1. Sep. 29, 2023C&O Reading Group - Noah Weninger

    Title: A Fast Combinatorial Algorithm for the Bilevel Knapsack Problem with Interdiction Constraints, Part II

    Speaker: Noah Weninger
    Affiliation: University of Waterloo
    Location: MC 6029

    Abstract: We consider the bilevel knapsack problem with interdiction constraints, a generalization of 0-1 knapsack. In this problem, there are two knapsacks and n items. The objective is to select some items to pack into the first knapsack (i.e. interdict) such that the maximum profit attainable from packing the remaining items into the second knapsack is minimized.

  2. Sep. 29, 2023Tutte Colloquium - Nikhil Kumar

    Title: An Approximate Generalization of the Okamura-Seymour Theorem

    Speaker: Nikhil Kumar
    Affiliation: University of Waterloo
    Location: MC 5501

    Abstract: We consider the problem of multicommodity flows in planar graphs. Okamura and Seymour showed that if all the demands are incident on one face, then the cut-condition is sufficient for routing demands.

  3. Oct. 2, 2023Algebraic Graph Theory - Maarten De Boeck

    Title: Neumaier graphs

    Speaker: Maarten De Boeck
    Affiliation: University of Memphis
    Location: Please contact Sabrina Lato for Zoom link

    Abstract: A Neumaier graph is an edge-regular graph with a regular clique. Several families of strongly regular graphs (but not all of them) are indeed Neumaier, but in 1981 it was asked whether there are Neumaier graphs that are not strongly regular. This question was only solved a few years ago by Greaves and Koolen, so now we know there are so-called strictly Neumaier graphs.

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