David Rees. 29 May 1918 — 16 August 2013
R. Y. Sharp · Biographical Memoirs of Fellows of the Royal Society · 2015
David Rees completed his Cambridge undergraduate studies in mathematics in summer 1939; in his first three months of postgraduate work in autumn 1939 he produced a characterization of completely 0-simple semigroups. War then intervened: he worked until the end of the war at Bletchley Park, the British codebreaking centre in Buckinghamshire, where he was part of a team that broke the Enigma code regularly for some critical months during 1940. After the war he first worked at Manchester University, but moved to Cambridge University in 1948. In the immediate postwar period, he continued with research into semigroups and non-commutative algebra. His first paper was very influential, and he is considered by semigroup theorists to be one of the founding fathers of their subject.