I. Piatetski-Shapiro, Yale educator, theorist who clashed with Soviets
NEW YORK - Dr. Ilya Piatetski-Shapiro, whose mathematical contributions stretched over a long career despite hardships as a Jew in the Soviet Union and later the debilitating effects of Parkinson's disease, died Feb. 21 in Tel Aviv. He was 79. His death was announced by Yale University, where he was a professor.
Working with Dr. James W. Cogdell, his collaborator over a quarter-century, starting in the mid-'70s, Dr. Piatetski-Shapiro shaped a proof of what is known as the Converse Theorem, which finds deep relationships between different fields of mathematics. The mathematical constructs are "quite mysterious, even to mathematicians," Cogdell explained in an interview this week.
But the theorem has wide applications, including playing a small but important role in the proof of Fermat's Last Theorem that Andrew Wiles, a Princeton mathematician, completed in 1994. "It's a very powerful tool," said Dr. Peter C. Sarnak, a professor of mathematics at Princeton.
Born in Moscow, Dr. Ilya Piatetski-Shapiro became interested in math when he was 10. In a memoir, he said that when he learned about negative numbers from his father, a chemical engineer, he was struck "by the charm and unusual beauty" of the concept. After completing his bachelor's degree in 1951 at Moscow University, he wanted to continue his graduate studies there. But the application was rejected.
"That was a time of great anti-Semitism," said Dr. Piatetski-Shapiro's son, Gregory.
He was eventually admitted to the Moscow Pedagogical Institute. But in 1952, he received a letter from officials ordering him to go to Kazakhstan to teach high school. His parents, fearing that he might be sent to Stalin's labor camps if he refused, told him to go, but he decided against it. After about a year, another letter told him he did not have to report for the assignment.
During this time, he produced a proof that asserts that certain sequences of integers defined through the power function contain an infinite number of prime numbers. "It was rather unexpected," Sarnak said.
Dr. Piatetski-Shapiro received his doctorate in 1954.
In 1958, he became a professor of mathematics at the Moscow Institute of Applied Mathematics, and in 1965 he gained an additional professorship at Moscow State University.
Except for a short trip to Hungary, Dr. Piatetski-Shapiro was not allowed to leave the Soviet Union. The authorities told him that he would be free to travel if he joined the Communist Party. He responded that party membership would distract him from his work.
In 1976, Dr. Piatetski-Shapiro finally received an exit visa.
Starting in 1977, he divided his time as a professor between Tel Aviv University and Yale.
Dr. Piatetski-Shapiro leaves his wife, Edith, , who lives in New Haven and Tel Aviv; his son, Gregory of Brookline, Mass.; a daughter, Shelly Shapiro of New York City; a stepdaughter, Niki Lipkin of Tel Aviv; and two grandsons.