James Anthony Dominic Welsh (known professionally as D.J.A. Welsh) (born 29 August 1938, died 30 November 2023 ^[1]) ^{[2] [3]} was an English mathematician and emeritus professor of Oxford University's Mathematical Institute. He was an expert in matroid theory, ^[4] the computational complexity of combinatorial enumeration problems, percolation theory, and cryptography.

Biography

Welsh obtained his Doctor of Philosophy from Oxford University under the supervision of John Hammersley. ^[5] After working as a researcher at Bell Laboratories, he joined the Mathematical Institute in 1963 and became a fellow of Merton College, Oxford in 1966. He chaired the British Combinatorial Committee from 1983 to 1987. ^[3] Welsh was given a personal chair in 1992 and retired in 2005. ^[3] He supervised 28 doctoral students. ^[6]

Books

• Matroid Theory (LMS Monographs, vol. 8, Academic Press, 1976, MR 0427112, reprinted by Dover Publications, 2010, ISBN  978-0486474397)
• Probability: An Introduction (with Geoffrey Grimmett, Oxford University Press, 1986, ISBN  0-19-853264-4, MR 0869591)
• Codes and Cryptography (Oxford University Press, 1988, ISBN  978-0198532873, MR 0959137)
• Complexity: Knots, Colourings and Counting (LMS Lecture Notes, vol. 186, Oxford University Press, 1993, ISBN  0-521-45740-8, MR 1245272)
• Complexity and Cryptography: An Introduction (with John Talbot, Cambridge University Press, 2006, MR 2221458) ^[7]

Awards and honours

Welsh received an honorary doctorate from the University of Waterloo in 2006. ^[3]

In 2007, Oxford University press published Combinatorics, Complexity, and Chance: A Tribute to Dominic Welsh, an edited volume of research papers dedicated to Welsh. ^[8]

The Russo–Seymour–Welsh estimate in percolation theory is partly named after Welsh.

References