Mathieu Rundström

I am a PhD student in the Combinatorics and Optimization department at the University of Waterloo, advised by Jim Geelen. My research is in combinatorics, more specifically structural and extremal graph and matroid theory.

Office: MC 5481
Email: mrundstr@uwaterloo.ca

Research

My current focus is on understanding the world surrounding regular matroids and delta-matroids. I also enjoy working on many more things, some of which include graph colouring and structural questions on tournaments.

In preparation

• The structure of almost-regular matroids (with J. Geelen).
• Induced subgraphs of graphs of large Kr-free chromatic number (with A. Chaniotis, T. LaGrange, and S. Spirkl).
• Excluded subtournaments for matching tournaments (with S. Spirkl, D. Vitorino, Y. Xing).

Submitted / Published

• The structure of Δ(1, 2, 2)-free tournaments (with S. Kim, T. LaGrange, A. Sadhukhan, S. Spirkl). Submitted. [arXiv:2511.03234]
• An improved upper bound for the multicolour Ramsey number of odd cycles (with M. Axenovich, W. Cames van Batenburg, O. Janzer, L. Michel). Published in Journal of Combinatorial Theory, Series B. [arXiv:2510.17981]