Paul Erdős
1913–1996, Budapest, Austria-Hungary (now Hungary), Warsaw, Poland
Itinerant Hungarian mathematician who authored more than 1,500 papers with over 500 collaborators, pioneering the probabilistic method in combinatorics, Ramsey theory, extremal graph theory, and an elementary proof of the prime number theorem.
Paul Erdős was born in Budapest to two high-school mathematics teachers. At eighteen, as an undergraduate at Pázmány Péter University, he found an elegant elementary proof of Bertrand's postulate — that there is always a prime between n and 2n — and earned his doctorate in 1934. Forced out of Hungary by rising antisemitism, he took a fellowship in Manchester and, in 1938, moved to the United States.
Erdős was a solver and poser of problems rather than a builder of abstract machinery, and his questions reshaped discrete mathematics. With George Szekeres (1935) he proved an early cornerstone of Ramsey theory; in 1947 he used random colourings to give a lower bound for Ramsey numbers, launching the probabilistic method; with Alfréd Rényi (1959–1960) he founded the theory of random graphs; and in 1949 he and Atle Selberg found the first elementary proof of the prime number theorem.
For most of his adult life Erdős had no permanent home or regular academic post, travelling from university to university with a single suitcase, announcing 'My brain is open', and offering small cash prizes for hundreds of open problems. He published around 1,500 papers — giving rise to the 'Erdős number' measuring collaborative distance from him — and gave away nearly all of his 1983 Wolf Prize money.
Workplaces: Hungarian Academy of Sciences, Technion – Israel Institute of Technology
Hungary