View source for David Rees (mathematician)

{{Other people|David Rees}}
{{EngvarB|date=July 2017}}
{{Use dmy dates|date=July 2017}}

{{Infobox scientist
| name              = David Rees
| image             = David_Rees_(mathematician).png
| image_size        = 
| caption           = Portrait by Godfrey Argent
| birth_date        = {{birth date|df=yes|1918|5|29}}
| birth_place       = [[Abergavenny]], Wales
| death_date        = {{death date and age|df=yes|2013|8|16|1918|5|29}}<ref>{{cite web | url = http://royalsociety.org/about-us/fellowship/notices-2013/ | title = 2013 death notices | publisher = Royal Society | accessdate = 20 August 2013 | quote = Professor David Rees FRS, 29 May 1918 – 16 August 2013 (elected 1968), Emeritus Professor of Pure Mathematics, University of Exeter, Council service: 1979 – 1981 }}</ref>
| death_place       = [[Exeter]], [[Devon]], England
| residence         = 
| citizenship       = 
| nationality       = 
| ethnicity         = 
| field             = 
| work_institutions = {{ubl|[[University of Manchester]]|[[University of Cambridge]]|[[University of Exeter]]}}
| alma_mater        = [[University of Cambridge]]
| doctoral_advisor  = {{Plainlist|
* [[Philip Hall]]
*[[Gordon Welchman]]<ref name=mathgene/>}}
| doctoral_students = {{Plainlist|
* [[Michael P. Drazin]]
* {{ill|O.A.S Karamzadeh|fa|امیدعلی شهنی کرم‌زاده|vertical-align=sup}}<ref name=mathgene>{{MathGenealogy|id=111836}}</ref>}}
| known_for         = {{Plainlist|
* [[Artin–Rees lemma]]
* [[Rees algebra]]
* [[Rees factor semigroup]]
* [[Rees matrix semigroup]]<ref name=s>{{SpringerEOM |title=Rees semi-group of matrix type |access-date=26 February 2021}}</ref>
* Rees's theorem<ref name=s/>}}
| author_abbrev_bot = 
| author_abbrev_zoo = 
| influences        = 
| influenced        = 
| prizes            = {{Plainlist|
* [[Fellow of the Royal Society|FRS]] <small>(1968)</small><ref name=frs>{{cite journal|last1=Sharp|first1=R. Y.|title=David Rees 29 May 1918 – 16 August 2013|journal=[[Biographical Memoirs of Fellows of the Royal Society]]|volume=61|year=2015|pages=379–401|publisher=Royal Society|issn=0080-4606|doi=10.1098/rsbm.2015.0010|s2cid=123809696|doi-access=free}}</ref>
* [[Pólya Prize (LMS)|Pólya Prize]] <small>(1993)</small>}}
| footnotes         = 
| signature         = 
| spouse            = {{marriage|Joan S. Cushen|1952}}
}}

'''David Rees''' [[Fellow of the Royal Society|FRS]]<ref name=frs/> (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 to 1983.<ref name="Sharp">{{cite journal |url=https://rsbm.royalsocietypublishing.org/content/roybiogmem/early/2015/06/18/rsbm.2015.0010.full.pdf |title=Obituary |author=R.Y. Sharp |journal=Biographical Memoirs of Fellows of the Royal Society |publisher=[[Royal Society]] |date=2015 |volume=61 |pages=379–401 |doi=10.1098/rsbm.2015.0010 |s2cid=123809696 |accessdate=30 March 2021}}</ref> During the [[Second World War]], Rees was active on [[Enigma machine|Enigma]] research in [[Hut 6]] at [[Bletchley Park]].<ref>{{cite web|author=Rodney Sharp |url=https://www.theguardian.com/education/2013/aug/29/david-rees |title=David Rees obituary &#124; Education |work=The Guardian |date=29 August 2013 |accessdate=30 August 2013}}</ref><ref>{{cite web|url=http://rollofhonour.bletchleypark.org.uk/search/record-detail/7604/|title=Bletchley Park Roll of Honour|publisher=Bletchley Park Trust|accessdate=2 August 2014}}</ref>

==Early life==
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 School, Abergavenny|King Henry VIII Grammar School]].<ref name="Sharp" />

==Education and career==
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 semigroup|completely simple]] and [[completely 0-simple semigroup|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 semigroup]]s.<ref name=s/><ref name="Nagy2001">{{cite book|author=Attila Nagy|title=Special classes of semigroups|url=https://books.google.com/books?id=BmyCMoEU1n4C&pg=PA14|year=2001|publisher=Springer|isbn=978-0-7923-6890-8|pages=14–15}}</ref>

Later in 1939, Welchman drafted Rees into [[Hut 6]], [[Bletchley Park]], for the war effort. He was credited with the first decode using the [[John Herivel#Herivel tip|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.<ref name="Sharp" /><ref name="Herivel">{{cite book |author=J. Herivel |title=Herivelismus and the German military Enigma |date=2008 |publisher=M. & M. Baldwin |location=Kidderminster |accessdate=}}</ref>

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]].<ref>Biographical memoirs of fellows of the Royal Society: Volume 53</ref> In 1954, in a joint paper with Northcott,<ref>{{cite journal | doi=10.1017/S0305004100029194 | author=Douglas Northcott and David Rees | title=Reductions of Ideals in Local Rings | journal=Mathematical Proceedings of the Cambridge Philosophical Society | volume=50 | number=2 | pages=145&ndash;158 | year=1954 | bibcode=1954PCPS...50..145N | s2cid=123098860 }}</ref> Rees introduced the Northcott–Rees theory of reductions and integral closures, which has subsequently been influential in [[commutative algebra]].<ref>{{cite news| url=https://www.independent.co.uk/news/obituaries/professor-douglas-northcott-220370.html | location=London | work=The Independent | title=Professor Douglas Northcott – Obituaries, News – The Independent}}</ref> 
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 [[Doctor of Science|DSc]] by the University of Cambridge.

[[Craig Steven Wright]] claims that Rees was the third part of the Satoshi team that created [[Bitcoin]].<ref>{{Cite web|url=https://www.finder.com/dr-craig-wright-explains-the-origins-of-bitcoin-full-interview|title=Dr. Craig Wright explains the origins of Bitcoin – Full interview {{!}} finder.com|last=Edwards|first=James|date=2019-04-27|website=finder US|language=en-US|access-date=2019-08-27}}</ref><ref>{{cite web | url=https://ramonquesada.com/english/who-was-prof-david-rees/ | title=Who was Prof. David Rees? | date=20 June 2020 }}</ref>

==Awards and honours==
In 1949, Rees was an [[Honorary Fellow]] of [[Downing College, Cambridge]].<ref>{{cite web |url=http://www.dow.cam.ac.uk/dow_server/mfs/honorary_fellows/D._Rees.html |title=Downing College |publisher=University of Cambridge |accessdate=30 August 2013 |url-status=dead |archiveurl=https://web.archive.org/web/20120316214247/http://www.dow.cam.ac.uk/dow_server/mfs/honorary_fellows/D._Rees.html |archivedate=16 March 2012 |df=dmy-all }}</ref>

In 1968, he was elected a [[List of Fellows of the Royal Society elected in 1968|Fellow of the Royal Society (FRS)]].<ref name=frs/>

In 1993, he was also awarded an [[List of honorary graduates of the University of Exeter#1990s|Honorary]] [[Doctor of Science|DSc]] by the [[University of Exeter]]. The same year, he was awarded the [[Pólya Prize (LMS)|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 life==
In 1952, Rees married Joan S. Cushen,<ref>GRO Register of Marriages: JUN 1952 4a 395 CAMBRIDGE – David Rees = Joan S. Cushen</ref> who became a Senior Lecturer in Mathematics at Exeter, with four children:
# (Susan) [[Mary Rees]] FRS, Professor of Mathematics at the [[University of Liverpool]], b. 1953<ref>GRO Register of Births: SEP 1953 4a 294 CAMBRIDGE – Susan M. Rees, mmn = Cushen</ref><ref>{{cite news| url=http://www.timesonline.co.uk/tol/news/uk/article844228.ece?token=null&offset=120 | location=London | work=The Times | first=Anushka | last=Asthana|author-link=Anushka Asthana | title=Academics – Times Online}}{{dead link|date=September 2024|bot=medic}}{{cbignore|bot=medic}}</ref><ref>{{cite web |url=http://www.liv.ac.uk/~maryrees/maryrees.homepage.html |title=Professor Mary Rees FRS |publisher=University of Liverpool |date= |accessdate=}}</ref>
# Rebecca Rees, b. 1955<ref>GRO Register of Births: DEC 1955 4a 222 CAMBRIDGE – Rebecca Rees, mmn = Cushen</ref>
# [[Sarah Rees]], Professor of Pure Mathematics at [[Newcastle University]], b. 1957<ref>GRO Register of Births: DEC 1957 4a 338 CAMBRIDGE – Sarah E. Rees, mmn = Cushen</ref><ref>{{cite web |url=http://www.mas.ncl.ac.uk/~nser/ |title=Prof. Sarah Rees |publisher=University of Newcastle upon Tyne |date= |accessdate=}}</ref>
# Deborah Rees, b. 1960<ref>GRO Register of Births: JUN 1960 7a 442 EXETER – Deborah Rees, mmn = Cushen</ref>

==External links==
* {{MacTutor Biography|id=Rees_David}}
* [https://rsbm.royalsocietypublishing.org/content/roybiogmem/early/2015/06/18/rsbm.2015.0010.full.pdf Obituary] by R.Y. Sharp, [[Royal Society]] &mdash; includes a photograph (p.&nbsp;3), and a detailed bibliography (p.&nbsp;23f)

==References==
{{reflist}}

{{University of Manchester|state=collapsed}}
{{University of Cambridge|state=collapsed}}
{{University of Exeter|state=collapsed}}
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{{DEFAULTSORT:Rees, David}}
[[Category:1918 births]]
[[Category:2013 deaths]]
[[Category:20th-century British mathematicians]]
[[Category:21st-century British mathematicians]]
[[Category:British cryptographers]]
[[Category:Bletchley Park people]]
[[Category:Fellows of the Royal Society]]
[[Category:Alumni of Sidney Sussex College, Cambridge]]
[[Category:Fellows of Downing College, Cambridge]]
[[Category:Academics of the University of Manchester]]
[[Category:Academics of the University of Cambridge]]
[[Category:Academics of the University of Exeter]]
[[Category:People from Abergavenny]]
[[Category:People educated at King Henry VIII School, Abergavenny]]
[[Category:Group theorists]]