  This biographical and scientific memoir of Dominic Welsh includes summaries
of his important contributions to probability and combinatorics. With John
Hammersley, he introduced first-passage percolation, and in so doing they
formulated and proved the first subadditive ergodic theorem. Welsh has numerous
results in matroid theory, and wrote the first monograph on the topic. He
worked on computational complexity and particularly the complexity of computing
the Tutte polynomial. He was an inspirational teacher and advisor who helped to
develop a community of scholars in combinatorics.
