- Alfréd Rényi
Alfréd Rényi (20 March 1921 – 1 February 1970) was a Hungarian
mathematician who made contributions incombinatorics andgraph theory but mostly inprobability theory . [citation|title=Obituary: Alfred Renyi|first=David|last=Kendall|journal=Journal of Applied Probability|volume=7|issue=2|year=1970|pages=508–522|url=http://links.jstor.org/sici?sici=0021-9002(197008)7%3A2%3C508%3AOAR%3E2.0.CO%3B2-Y.] [citation|title=Alfred Renyi, 1921-1970|first1=P.|last1=Revesz|first2=I.|last2=Vincze|journal=The Annals of Mathematical Statistics|volume=43|issue=6|year=1972|url=http://links.jstor.org/sici?sici=0003-4851(197212)43%3A6%3C%3AAR1%3E2.0.CO%3B2-1|pages=i–xvi.]Rényi was born in
Budapest to Artur Rényi and Barbara Alexander; his father was a mechanical engineer while his mother was the daughter of a philosopher and literary critic, Bernát Alexander.He was prevented from enrolling in university in 1939 due to the anti-Jewish laws then in force, but enrolled at the University of Budapest in 1940 and finished his studies in 1944. At this point he was imprisoned in a labor camp, escaped, and completed hisPh.D. in 1947 at theUniversity of Szeged , under the advisement ofFrigyes Riesz . [MathGenealogy |id=51155] He married Katalin Schulhof, herself a mathematician, in 1946; his daughter Zsuzsa was born in 1948. After a brief assistant professorship at Budapest, he was appointed Professor Extraordinary at theUniversity of Debrecen in 1949.He proved, using the
large sieve , that there is a number such that every even number is the sum of a prime number and a number that can be written as the product of at most primes. See alsoGoldbach conjecture .In
information theory , he introduced the spectrum of Rényi entropies of order α, giving an important generalisation of theShannon entropy and theKullback-Leibler divergence . The Rényi entropies give a spectrum of usefuldiversity indices , and lead to a spectrum offractal dimension s.He founded the Mathematical Institute in
Budapest , now called The Alfréd Rényi Institute of Mathematics. There are currently approximately 70 mathematicians doing research at the Institute.He wrote 32 joint papers with
Paul Erdős , [http://www.oakland.edu/enp/erdtrib.pdf.] the most well-known of which are his papers introducing theErdős–Rényi model ofrandom graph s. ["On random graphs", Publ. Math. Debrecen, 1959, and "On the evolution of random graphs", Publ. Math. Inst. Hung. Acad. Sci, 1960.] Alfréd Rényi is probably the source of the quote: [http://en.wikiquote.org/wiki/Paul_Erd%C5%91s "A mathematician is a device for turning coffee into theorems."] , which is generally ascribed to Erdős.He is also famous for having said, "If I feel unhappy, I do mathematics to become happy. If I am happy, I do mathematics to keep happy." [Quoted in
Pál Turán , "The Work of Alfréd Rényi", Matematikai Lapok 21 (1970) 199 - 210.]References
External links
* [http://www.math.elte.hu/probability/renyi/racv.html The life of Alfréd Rényi] , by
Pál Turán
*MacTutor Biography|id=Renyi
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