# Rényi, Alfréd

(Budapest, March 20th, 1921 – Budapest, February 1st, 1970)

Mathematician, who made important contributions in combinatorics, graph theory, but mostly in theory of probabilizy and information, professor in Debrecen and Budapest, academician; founder of the school of probability theory.

Alfréd Rényi received a literary, rather than scientific education. He was the only child of Artur Rényi, a mechanical engineer, and Barbara Alexander, daughter of the philosopher and literary critic Bernát Alexander.

In 1939, he finished secondary school in Budapest with outstanding marks. After graduation he won a competition in Greek language and worked half a year in the Ganz Shipyard in Budapest. He was admitted to the University of Science in Budapest the autumn 1940 to study mathematics and physics, and from 1940 on he was a student of Lipót Fejér.

In 1944 he was forced to a Labour Camp but somehow managed to escape.

After the World War II, Rényi earned his Ph. D. degree at University of Szeged under Frigyes Riesz in 1945 for work on Cauchy-Fourier series.

In 1946 he made research in Leningrad under the supervision of J.V. Linnik and I.M.Vinogradov on the number theory. In his 1947 thesis he solved the so-called quasi Goldbach conjecture.

In the autumn of 1947 he became a professor at the University of Science in Budapest and in 1949, at the University of Debrecen, as well.

From 1950 Rényi was appointed the Director Institute of Applied Mathematics, from 1952 he also headed the Department of Probability Theory at the Loránd Eötvös University of Sciences, both positions he kept until his death. Later the Institute was named Alfred Rényi Institute of Mathematics Hungarian Academy of Science

His scientific work departed from number theory and covers almost all of mathematics; he has made relevant contributions in several branches of analysis, combinatorics, graph, number and probality theory. He was founder of the Hungarian Probability Theory School. He is best known for proving that every even integer is the sum of a prime and an almost prime number (one with only two prime factors).

He published 32 joint papers with Paul Erdős e.g. They wrote on random graphs and also considered random space filling curves.

His was active in scientific public life. He dealt with philosophy of mathematics and initiated researches in ancient mathematics. Together with others he urged the "*new math in school*", a novel method in teaching mathematics.

In his remembrance the Academy established the Alfréd Rényi Prize.

Memberships: Member of the Hungarian Academy of Sciences (correspondent member 1949, full member 1956). Head of the International Statistical Institute (1965-1969). Secretary (1949-55) and later managing President of the János Bolyai Mathematical Society, and member of the Hungarian Scientific Accreditation Committee.

At various times visiting professor at the Universities of Michigan, North Carolina and Stanford, at Erlangen University in Germany. Fellow of the Institute of Mathematical Statistics, as well as, Fellow at Churchill College at the University of Cambridge.

He was the editor of numerous journals in Hungary and abroad as well: editor of Studia Scientiarum Mathematica Hungarica, member of the editorial boards of Acta Mathematica, Annales Sci. Math., Publicationes Math., Matematikai Lapok, Zeitschrift für Wahrscheinlichkeitstheorie, Journal of Applied Probability, Journal of Combinatorial Analysis and Information and Control.

*Awards:* Kossuth Award (1949, 1954)

*Selected bibliography:*

*List of Publications of Alfréd Rényi*. URL: http://www.math.elte.hu/probability/renyi/ralp.html (more than 300 title)
- His "Dialogues about Mathematics", "Letters about Mathematics", and "Diary on Information Theory" were published in German, French, Russian, English, Italian, and Rumanian.
- His textbook entitled "
*Valószínűségszámítás*" (*Probability Calculation*) (Budapest, Tankönyvkiadó, 1966.) is regarded as a basic textbook work in the Hungarian language.

*References:*

- Alfréd Rényi. 1921-1970, Studia Sci. Math. Hungar
**5** (1970), 4.
- N. H. Bingham, The work of Alfréd Rényi: some aspects in probability and number theory,
*Studia Sci. Math. Hungar*. **26** (1991), 165-183.
- B. Gyires, Alfréd Rényi (1920-1970),
*Publ. Math. Debrecen* **17** (1970), 1-17.
- D G Kendall, Obituary: Alfréd Rényi,
*Journal of Applied Probability* **7** (1970), 509-522.
- P. Medgyessy, Alfréd Rényi's work',
*Studia Sci. Math. Hungar*. **6** (1971), 3-22.
- P. Medgyessy, Addendum: 'Alfréd Rényi's work',
*Studia Sci. Math. Hungar*. **7** (1972), 477.
- V. B. Mészáros, The work of Alfréd Rényi. V. In remembrance of Alfréd Rényi (Hungarian),
*Mat. Lapok* **21** (1970), 245-248.
- P. Révész and I. Vincze, Alfréd Rényi, 1921-1970,
*Ann. Math. Statist*. *43* (6) (1972), i-xvi.
- L. Schmetterer, Alfréd Rényi, in memoriam,
*Proceedings of the Sixth Berkeley Symposium on Mathematical Statistics and Probability* Vol. II (Berkeley, 1972), xxv-1.
- The works of Alfréd Rényi (1921-1970),
*Mat. Lapok* **21** (1970), 1-18.

**managed to escape**

He got false papers and hid for six months avoiding capture. During this time his parents were kept confined in the Budapest ghetto. Rényi rescued them with an extreme and brave manner: *got hold of a soldier's uniform, walked into the ghetto, and marched his parents out*.