Dominic Welsh: his work and influence
Graham Farr, Dillon Mayhew, James Oxley
TL;DR
This tribute surveys Dominic Welsh’s four-phase career—discrete probability, matroid theory, computational complexity, and Tutte–Whitney polynomials—and his role in linking these domains. It emphasizes his foundational texts on matroids and the Tutte polynomial, his subadditive approach to first-passage percolation, and his pioneering complexity classifications for evaluations of $T(M;x,y)$ and related polynomials via the Tutte plane and hyperbola $H_q=ig\\{(x,y) \\\mid (x-1)(y-1)=q\\}\ig ext{.}$. Welsh’s influence extended through a large, mentoring student network and his expository work, including influential surveys and diagrams; he fostered connections with physics, coding theory, and knot theory. The work argues that he was a 'complete mathematician' whose ideas and community-building reshaped discrete mathematics and its reach.
Abstract
We review the work of Dominic Welsh (1938-2023), tracing his remarkable influence through his theorems, expository writing, students, and interactions. He was particularly adept at bringing different fields together and fostering the development of mathematics and mathematicians. His contributions ranged widely across discrete mathematics over four main career phases: discrete probability, matroids and graphs, computational complexity, and Tutte-Whitney polynomials. We give particular emphasis to his work in matroid theory and Tutte-Whitney polynomials.
