James Anthony Dominic Welsh (known professionally as D.J.A. Welsh) (born 29 August 1938)Prof Dominic J A Welsh

Debrett's Debrett's () is a British professional coaching company, publisher and authority on etiquette and behaviour, founded in 1769 with the publication of the first edition of ''The New Peerage''. The company takes its name from its founder, John Deb ...

, retrieved 2012-03-11. is an English

mathematician A mathematician is someone who uses an extensive knowledge of mathematics in their work, typically to solve mathematical problems. Mathematicians are concerned with numbers, data, quantity, structure, space, models, and change. History On ...

and emeritus professor of

Oxford University Oxford () is a city in England. It is the county town and only city of Oxfordshire. In 2020, its population was estimated at 151,584. It is north-west of London, south-east of Birmingham and north-east of Bristol. The city is home to the ...

Mathematical Institute The Mathematical Institute is the mathematics department at the University of Oxford in England. It is one of the nine departments of the university's Mathematical, Physical and Life Sciences Division. The institute includes both pure and appl ...

. He is an expert in

matroid In combinatorics, a branch of mathematics, a matroid is a structure that abstracts and generalizes the notion of linear independence in vector spaces. There are many equivalent ways to define a matroid axiomatically, the most significant being ...

theory,. the

computational complexity In computer science, the computational complexity or simply complexity of an algorithm is the amount of resources required to run it. Particular focus is given to computation time (generally measured by the number of needed elementary operations) ...

of combinatorial enumeration problems,

percolation theory In statistical physics and mathematics, percolation theory describes the behavior of a network when nodes or links are added. This is a geometric type of phase transition, since at a critical fraction of addition the network of small, disconnected ...

, and

cryptography Cryptography, or cryptology (from grc, , translit=kryptós "hidden, secret"; and ''graphein'', "to write", or ''-logia'', "study", respectively), is the practice and study of techniques for secure communication in the presence of adver ...

Biography

Welsh obtained his Doctor of Philosophy from Oxford University under the supervision of

John Hammersley John Michael Hammersley, (21 March 1920 – 2 May 2004) was a British mathematician best known for his foundational work in the theory of self-avoiding walks and percolation theory. Early life and education Hammersley was born in Helensburgh i ...

. After working as a researcher at

Bell Laboratories Nokia Bell Labs, originally named Bell Telephone Laboratories (1925–1984), then AT&T Bell Laboratories (1984–1996) and Bell Labs Innovations (1996–2007), is an American industrial research and scientific development company owned by mult ...

, he joined the Mathematical Institute in 1963 and became a fellow of

Merton College, Oxford Merton College (in full: The House or College of Scholars of Merton in the University of Oxford) is one of the Colleges of Oxford University, constituent colleges of the University of Oxford in England. Its foundation can be traced back to the ...

in 1966. He chaired the British Combinatorial Committee from 1983 to 1987. Welsh was given a personal chair in 1992 and retired in 2005. He supervised 28 doctoral students.

Books

*''Matroid Theory'' (LMS Monographs, vol. 8, Academic Press, 1976, , reprinted by Dover Publications, 2010, ) *''Probability: An Introduction'' (with Geoffrey Grimmett, Oxford University Press, 1986, , ) *''Codes and Cryptography'' (Oxford University Press, 1988, , ) *''Complexity: Knots, Colourings and Counting'' (LMS Lecture Notes, vol. 186, Oxford University Press, 1993, , ) *''Complexity and Cryptography: An Introduction'' (with John Talbot, Cambridge University Press, 2006, )Review of ''Complexity and Cryptography'' by J. Rothe (2007), ''SIGACT News'' 38 (2): 16–20, .

Awards and honours

Welsh received an honorary doctorate from the

University of Waterloo The University of Waterloo (UWaterloo, UW, or Waterloo) is a public research university with a main campus in Waterloo, Ontario Waterloo is a city in the Canadian province of Ontario. It is one of three cities in the Regional Municipality ...

in 2006. In 2007, Oxford University press published ''Combinatorics, Complexity, and Chance: A Tribute to Dominic Welsh'', an edited volume of research papers dedicated to Welsh. The Russo–Seymour–Welsh estimate in percolation theory is partly named after Welsh.

References

{{DEFAULTSORT:Welsh, Dominic James Anthony 1938 births Living people English mathematicians Alumni of Merton College, Oxford Fellows of Merton College, Oxford Combinatorialists