David Rees (mathematician)

David Rees FRS[3] (29 May 1918 – 16 August 2013) was a British professor of pure mathematics at the University of Exeter, having been head of the Mathematics / Mathematical Sciences Department at Exeter from 1958-1983.[5] During the Second World War, Rees was active on Enigma research in Hut 6 at Bletchley Park.[6][7]

David Rees
Born(1918-05-29)29 May 1918
Died16 August 2013(2013-08-16) (aged 95)[1]
Exeter, Devon, England
Alma materUniversity of Cambridge
Known for
Joan S. Cushen
(m. 1952)
Scientific career
Doctoral advisor
Doctoral students

Early lifeEdit

Rees was born in Abergavenny to David Rees (1881-), a corn merchant, and his wife Florence Gertrude (Gertie) née Powell (1884-1970), the 4th out of 5 children. Despite periods of ill health and absence, he successfully completed his early education at King Henry VIII Grammar School.[5]

Education and careerEdit

Rees won a scholarship to Sidney Sussex College, Cambridge, supervised by Gordon Welchman and graduating in summer 1939. On completion of his education, he initially worked on semigroup theory; the Rees factor semigroup is named after him. He also characterised completely simple and completely 0-simple semigroups, in what is nowadays known as Rees's theorem. The matrix-based semigroups used in this characterisation are called Rees matrix semigroups.[2][8]

Later in 1939, Welchman drafted Rees into Hut 6, Bletchley Park, for the war effort. He was credited with the first decode using the Herivel Tip. He was subsequently seconded to the Enigma Research Section, where the Abwehr Enigma was broken, and later to the Newmanry, where the Colossus computer was built.[5][9]

After the war, Rees was appointed an assistant lecturer at Manchester University in 1945 and a full lecturer at University of Cambridge in 1948. In 1949, he was a Fellow of Downing College.

At the behest of Douglas Northcott he switched his research focus to commutative algebra.[10] In 1954, in a joint paper with Northcott, Rees introduced the Northcott-Rees theory of reductions and integral closures, which has subsequently been influential in commutative algebra.[11] In 1956 he introduced the Rees decomposition of a commutative algebra.

In 1958, Rees and his family moved to Exeter, where he had been appointed to the Chair of Pure Mathematics. In 1959, he was awarded a DSc by the University of Cambridge.

According to Craig Steven Wright, Rees was the third part of the Satoshi team that created Bitcoin.[12]

Awards and honoursEdit

In 1949, Rees was an Honorary Fellow of Downing College, Cambridge.[13]

In 1968, he was elected a Fellow of the Royal Society (FRS).[3]

In 1993, he was also awarded an Honorary DSc by the University of Exeter. The same year, he was awarded the Pólya Prize by the London Mathematical Society. In August 1998 a conference on Commutative Algebra was held at Exeter in honour of David Rees' 80th Year.

Personal lifeEdit

In 1952, Rees married Joan S. Cushen,[14] who became a Senior Lecturer in Mathematics at Exeter, with four children:

  1. (Susan) Mary Rees FRS, Professor of Mathematics at the University of Liverpool, b. 1953[15][16][17]
  2. Rebecca Rees, b. 1955[18]
  3. Sarah Rees, Professor of Pure Mathematics at Newcastle University, b. 1957[19][20]
  4. Deborah Rees, b. 1960[21]

External linksEdit

  • O'Connor, John J.; Robertson, Edmund F., "David Rees (mathematician)", MacTutor History of Mathematics archive, University of St Andrews
  • Obituary by R.Y. Sharp, Royal Society — includes a photograph (p. 3), and a detailed bibliography (p. 23f)


  1. ^ "2013 death notices". Royal Society. Retrieved 20 August 2013. Professor David Rees FRS, 29 May 1918 – 16 August 2013 (elected 1968), Emeritus Professor of Pure Mathematics, University of Exeter, Council service: 1979 – 1981
  2. ^ a b c "Rees semi-group of matrix type", Encyclopedia of Mathematics, EMS Press, 2001 [1994], retrieved 26 February 2021
  3. ^ a b c Sharp, R. Y. (2015). "David Rees 29 May 1918 – 16 August 2013". Biographical Memoirs of Fellows of the Royal Society. Royal Society. 61: 379–401. doi:10.1098/rsbm.2015.0010. ISSN 0080-4606. S2CID 123809696.
  4. ^ a b David Rees at the Mathematics Genealogy Project
  5. ^ a b c R.Y. Sharp (2015). "Obituary" (PDF). Royal Society. Retrieved 30 March 2021.
  6. ^ Rodney Sharp. "David Rees obituary | Education". The Guardian. Retrieved 30 August 2013.
  7. ^ "Bletchley Park Roll of Honour". Bletchley Park Trust. Retrieved 2 August 2014.
  8. ^ Attila Nagy (2001). Special classes of semigroups. Springer. pp. 14–15. ISBN 978-0-7923-6890-8.
  9. ^ J. Herivel (2008). Herivelismus and the German military Enigma. Kidderminster: M. & M. Baldwin.
  10. ^ Biographical memoirs of fellows of the Royal Society: Volume 53
  11. ^ "Professor Douglas Northcott – Obituaries, News – The Independent". The Independent. London.
  12. ^ Edwards, James (27 April 2019). "Dr. Craig Wright explains the origins of Bitcoin – Full interview | finder.com". finder US. Retrieved 27 August 2019.
  13. ^ "Downing College". University of Cambridge. Archived from the original on 16 March 2012. Retrieved 30 August 2013.
  14. ^ GRO Register of Marriages: JUN 1952 4a 395 CAMBRIDGE – David Rees = Joan S. Cushen
  15. ^ GRO Register of Births: SEP 1953 4a 294 CAMBRIDGE – Susan M. Rees, mmn = Cushen
  16. ^ Asthana, Anushka. "Academics – Times Online". The Times. London.
  17. ^ "Professor Mary Rees FRS". University of Liverpool.
  18. ^ GRO Register of Births: DEC 1955 4a 222 CAMBRIDGE – Rebecca Rees, mmn = Cushen
  19. ^ GRO Register of Births: DEC 1957 4a 338 CAMBRIDGE – Sarah E. Rees, mmn = Cushen
  20. ^ "Prof. Sarah Rees". University of Newcastle upon Tyne.
  21. ^ GRO Register of Births: JUN 1960 7a 442 EXETER – Deborah Rees, mmn = Cushen