Gregory Chudnovsky

Gregory Chudnovsky Volfovich (also Choodnovsky ; Ukrainian Григорій Вольфович Чудновський / Hryhorij Wolfowytsch Tschudnowskyj ; Russian Григорий Вольфович Чудновский * 17th April 1952 in Kiev , Ukrainian SSR ) is an American mathematician who deals with number theory employs.

Chudnovsky, whose mother was a civil engineer and moved to New York with her sons, grew up in Ukraine. While still a high school student, he published his first mathematical work at the age of 16 and solved Hilbert's 10th problem at the age of 17 , roughly at the same time as Yuri Matiyasevich , who became famous for his work in 1972. Chudnovsky studied like his brother David Chudnovsky , with whom he subsequently worked closely, at the University of Kiev (diploma 1974) and received his doctorate in 1975 at the Mathematical Institute of the Ukrainian Academy of Sciences . Gregory Chudnovsky is severely handicapped by an illness ( myasthenia gravis ), and in order to ensure better medical care, the family applied to emigrate in 1976, whereupon they lost their jobs and were persecuted by the KGB, for example his mother was on one occasion Road beaten up. However, the family received support from foreign mathematicians such as Edwin Hewitt , with whom Chudnovsky worked in Kiev in 1976 and who mobilized a US senator on the matter, and they also received support from Andrei Sakharov . In 1977 they were able to travel to New York, where the brothers worked at Columbia University (until the 1990s only as Senior Research Scientists). In 1981 Gregory Chudnovsky received a lavish MacArthur Fellowship for five years . Despite the efforts of influential mathematicians ( Herbert Robbins wrote to the members of the National Academy of Sciences in 1986 , and Mark Kac and Lipman Bers tried unsuccessfully to raise private sponsorship money for a chair), the Chudnovskys initially did not get permanent employment at a New Yorker that matched their abilities or at a US university at all, which was partly attributed to Gregory Chudnovsky's disability and the fact that they only wanted to fill such a position together.

He is currently (2009) like his brother a professor at the Polytechnic Institute of New York University . They became known for several records in calculating Pi , some of which they achieved on supercomputers built in their apartment (called “M zero”, initially with 8 processors, it achieved up to 2 gigaflops of computing power) in the early 1990s. They had previously drawn attention to himself in the spring of 1989, when they set up with the calculation of 480 million digits of Pi a new record, in a time internationally-run competition, previously the team of Japanese Yasumasa Kanada of the University of Tokyo led, the one Hitachi supercomputers used. Canada countered shortly thereafter with over 1 billion jobs, which was surpassed by the Chudnovskys at the end of 1989. In mid-1991 they calculated pi to 2 billion 260 million digits and stopped the calculations for the time being.

For their calculations of pi, they used an algorithm they had developed ( Chudnovsky algorithm ), a formula that gives pi as a hypergeometric series similar to those already found by S. Ramanujan .

After their first home supercomputer, they were also involved in other computer projects. Shortly afterwards, together with Saed Younis (then a student at MIT ) and the IBM supercomputer architect Monty Denneau , they built the Little Fermat computer at MIT , which was specially built for number theory calculations . Gregory Chudnovsky was primarily interested in discovering patterns in the pi digit sequence (but he did not find any statistically significant patterns).

Chudnovsky made important contributions to the theory of transcendent numbers since the 1970s and proved, among other things, the transcendence of the value of the gamma function at the point 1/4.

Your help with the restoration of the unicorn carpets of the Metropolitan Museum of Art (in the digital photo documentation) was the subject of a PBS television film in 2003.

The brothers received the French Peccot-Vimont Prize, several Guggenheim Fellowships and the Moscow Mathematical Society Prize. In 1994 Gregory Chudnovsky received the George Pólya Prize . In 1978 he was invited speaker at the International Congress of Mathematicians in Helsinki ( Algebraic independence of values ​​of algebraic and elliptic functions ).

In 1982 the brothers were co-editors of the collected works of Sakharov at Dekker.

Fonts

• as editor with David Chudnovsky: The Riemann Problem, complete Integrability and Arithmetic Applications. Proceedings of a seminar, held at the Institut des Hautes Etudes Scientifiques, Bures-sur Yvette, France and at Columbia University, New York, USA, 1979–1980 (= Lecture Notes in Mathematics . 925). Springer, Berlin et al. 1982, ISBN 3-540-11483-1 .
• Contributions to the theory of transcendental numbers (= Mathematical Surveys and Monographs. 19). American Mathematical Society, Providence RI 1984, ISBN 0-8218-1500-8 .
• as editor with David Chudnovsky: Classical and Quantum Models of Arithmetic Problems (= Lecture Notes in Pure and Applied Mathematics. 92). Marcel Dekker, New York NY et al. 1984, ISBN 0-8247-1825-9 .
• as editor with David Chudnovsky: Search theory. Some recent developments (= Lecture Notes in Pure and Applied Mathematics. 112). Marcel Dekker, New York NY et al. 1989, ISBN 0-8247-8000-0 .

Web links

• Homepage at the Polytechnic Institute, NYU
• Links to the Chudnovskys at the Polytechnic Institute, NYU
• Richard Preston in the New Yorker 1992 about the Chudnovskys and their supercomputer, Mountains of Pi
• Portrait of the brothers at Nova Science

Individual evidence

1. ^ Richard Preston : Mountains of Pi. In: The New Yorker , March 2, 1992.
2. ^ Benjamin H. Yandell: The honors class. Hilbert's problems and their solvers. AK Peters, Natick MA 2002, ISBN 1-56881-141-1 , p. 113, doubts the independence of Chudnovsky, since Matiiasevich was circulating preprints of his work at that time and Chudnovsky's methods were similar to those of Matiiasevich. In addition, Chudnovsky claimed to have obtained the proof by proving that a polynomial by Martin Davis (1950) has finitely many solutions. According to Yandell, however, no publication is known in which this is shown.
3. ^ Richard Preston: Mountains of Pi. In: The New Yorker , March 2, 1992.
4. ↑ At that time still on two supercomputers, a Cray 2 in the Minnesota Supercomputer Center in Minneapolis and an IBM 3090 VF supercomputer in the Thomas J. Watson Research Center
5. ↑ Chudnovsky, Chudnovsky: The computation of classical constants. In: Proceedings of the National Academy of Sciences of the United States of America . Vol. 86, No. 21, 1989, pp. 8178-8182, JSTOR 34831 .
6. ↑ and an article about the brothers in the New Yorker , Nov. 4, 2005