For other persons named David/Dai Rees, see David/Dai ReesDavid Rees ScD Cantab, FIMA, FRS (29 May 1918 – 16 August 2013) was an emeritus professor of pure mathematics at the University of Exeter, having been head of the Mathematics / Mathematical Sciences Department at Exeter for many years. During the Second World War, Rees was active on Enigma research in Hut 6 at Bletchley Park.