Viggo Brun
{{Short description|Norwegian mathematician (1885–1978)}}{{Infobox scientist
| name = Viggo Brun
| image = Viggo Brun 1927-05-25.jpg
| birth_date = 13 October 1885
| birth_place = Lier, Norway
| death_date = {{d-da|15 August 1978|13 October 1885}}
| death_place = Drøbak, Norway
| citizenship = Norway
| fields = Number Theory
| known_for = Brun's Theorem, Brun Sieve
}}
Viggo Brun (13 October 1885 – 15 August 1978) was a Norwegian professor, mathematician and number theorist.
|access-date= January 1, 2017 }}
Contributions
In 1915, he introduced a new method, based on Legendre's version of the sieve of Eratosthenes, now known as the Brun sieve, which addresses additive problems such as Goldbach's conjecture and the twin prime conjecture. He used it to prove that there exist infinitely many integers n such that n and n+2 have at most nine prime factors, and that all large even integers are the sum of two numbers with at most nine prime factors.{{cite web |author1=J J O'Connor |author2=E F Robertson |title=Viggo Brun |url=http://www-groups.dcs.st-and.ac.uk/history/Biographies/Brun.html |archive-url=https://web.archive.org/web/20170116172225/http://www-groups.dcs.st-and.ac.uk/history/Biographies/Brun.html |archive-date=2017-01-16 |access-date=January 1, 2017 |publisher=School of Mathematics and Statistics, University of St Andrews, Scotland}}
He also showed that the sum of the reciprocals of twin primes converges to a finite value, now called Brun's constant: by contrast, the sum of the reciprocals of all primes is divergent. He developed a multi-dimensional continued fraction algorithm in 1919–1920 and applied this to problems in musical theory. He also served as praeses of the Royal Norwegian Society of Sciences and Letters in 1946.{{cite encyclopedia|year=1996|title=Vitenskapsselskapet|encyclopedia=Trondheim byleksikon|author=Bratberg, Terje|editor=Arntzen, Jon Gunnar|publisher=Kunnskapsforlaget|location=Oslo|pages=599–600|isbn=82-573-0642-8}}
Biography
Brun was born at Lier in Buskerud, Norway. He studied at the University of Oslo and began research at the University of Göttingen in 1910. In 1923, Brun became a professor at the File:ViggoBrun.jpg Technical University in Trondheim and in 1946 a professor at the University of Oslo.{{cite web|url= https://snl.no/Viggo_Brun|title= Viggo Brun|publisher = Store norske leksikon|access-date= January 1, 2017 }}
He retired in 1955 at the age of 70 and died in 1978 (at 92 years-old) at Drøbak in Akershus, Norway.{{cite web|url= https://nbl.snl.no/Viggo_Brun
|title= Viggo Brun|publisher = Norsk biografisk leksikon |author= Bent Birkeland|access-date= January 1, 2017 }}
See also
Fotnoter
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References
{{Reflist}}
Other sources
- H. Halberstam and H. E. Richert, Sieve methods, Academic Press (1974) {{ISBN|0-12-318250-6}}. Gives an account of Brun's sieve.
- C.J. Scriba, Viggo Brun, Historia Mathematica 7 (1980) 1–6.
- [http://www.numbertheory.org/obituaries/OTHERS/brun/ C.J. Scriba, Zur Erinnerung an Viggo Brun, Mitt. Math. Ges. Hamburg 11 (1985) 271-290]
External links
- {{MacTutor|id=Brun}}
- [https://web.archive.org/web/20030304091118/http://planetmath.org/encyclopedia/BrunsConstant.html Brun's Constant]
- [https://web.archive.org/web/20040604064319/http://planetmath.org/encyclopedia/BrunsPureSieve.html Brun's Pure Sieve]
- [http://arkivportalen.no/side/arkiv/detaljer?arkivId=no-NTNU_arkiv000000061437 Viggo Brun personal archive] exists at NTN University Library [https://www.ntnu.no/ub/bibliotek/dora Dorabiblioteket]
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{{s-ttl|title=Praeses of the Royal Norwegian Society of Sciences and Letters|years=1946}}
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Category:People from Lier, Norway
Category:Norwegian mathematicians
Category:20th-century Norwegian mathematicians
Category:University of Oslo alumni
Category:Academic staff of the Norwegian Institute of Technology
Category:Academic staff of the University of Oslo