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27.09.2012

In the spring of 2000, Prof. Victor Zalgaller had an extraordinary dream: It revealed to him the proof of a geometrical theorem. The revelation was not entirely out of the blue; Zalgaller had spent an entire year thinking about that theorem day and night. Armed with Zalgaller’s proof, a colleague of his managed to solve a 50-year-old mathematical problem. Their joint success, its results published later in the prestigious *Annals of Mathematics*, was one of the best presents Zalgaller received for his 80^{th} birthday.

A more formal celebration, a mathematical meeting in honor of his 80^{th} birthday, was held at the Weizmann Institute of Science in December 2000. When Zalgaller had immigrated to Israel from Russia a year earlier, he had been appointed a Consultant in the Institute’s Department of Mathematics.

Zalgaller’s ties with some of Weizmann’s mathematicians go back a long way: Back in 1946, Prof. Michael Solomyak had decided to become a mathematician after studying in a mathematics class for ninth-graders taught by Zalgaller at the Leningrad Pioneer Palace. Other faculty members and students at Weizmann know Zalgaller through his contributions to various areas of mathematics, including convex polyhedra, linear and dynamic programming, differential geometry and isoperimetry. He is perhaps best known for the 1980 book *Geometric Inequalities *that he co-authored with a former student, considered a classic and translated into English.

Victor Abramovich Zalgaller’s lengthy journey to geometry reflects the many tribulations Soviet mathematics went through in the 20^{th} century. As a youngster, he had joined one of the evening mathematics classes created in Russia in the mid-1930s to remedy the abysmal state of higher education, including mathematics, resulting from the Bolshevik policy of admitting students to university on the basis of ideology and class origins rather than ability. In 1936, he was among the winners of one of the first Leningrad Mathematics Olympiads for high school students.

His studies at Leningrad State University were interrupted by World War II. In early July 1941, after the Nazis invaded the USSR, he volunteered for the Red Army and spent the next four years in the artillery on the front line, sustaining a severe injury and earning five military decorations for bravery. In his memoirs *Wartime Life*, published in the United States in 1972, he documents his experiences in chilling detail, from the 1941 defense of the Leningrad District to the 1945 march through defeated Germany.

Upon return to university, Zalgaller’s status as a war veteran helped to make up for the two major obstacles he faced in his career as a mathematician in the Soviet Union: being Jewish and being the son of a father who in 1931, on trumped-up charges of propaganda for Poland, had been sent to the Gulag and had never been allowed to return to Leningrad. These “shortcomings” notwithstanding, in 1948 Zalgaller joined the Leningrad branch of the Steklov Institute of Mathematics, affiliated with the USSR Academy of Sciences, where he was to work for more than 50 years. From the 1970s, he also served as a professor at Leningrad University, where he was one of the most popular lecturers.

Early in his career, he worked under the guidance of famous mathematician Leonid Kantorovich, who was later to win the Nobel Prize in Economic Sciences. In 1951, they co-authored *Economic Cutting of Industrial Stocks*, one of the first books in the world on this topic. “I’m proud that upon receiving the Nobel Prize, Kantorovich named me among those who had helped him,” Zalgaller recalls.

He also considers himself fortunate to have worked closely with yet another famous Soviet mathematician, Alexander Danilovich Alexandrov. In 1962, they co-authored a book in Zalgaller’s main area of research, geometry: *Intrinsic Geometry of Surfaces*.

In addition to co-writing the three books, Zalgaller has translated another three and served as scientific editor of twelve more; his small book, *Theory of Envelopes*, is still widely used by engineers. He has authored more than 100 research papers; five of these papers were published after he turned 80.

Since making Aliya, Zalgaller lives in Rehovot. His wife Sofia-Maia is also a mathematician; in 1980, they co-authored a paper, later translated into French, in which they proposed the first algorithm for solving the Rubik’s cube puzzle from any initial position. They have a daughter, Tatiana, a computer specialist in the hi-tech industry, as well as a grandson and four great-grandchildren.

Zalgaller’s 90^{th} birthday was marked at the Weizmann Institute by a mathematical meeting that focused on his contributions to research. But on the same occasion, his colleagues also praised his qualities as a human being, particularly his exceptional honesty and his generosity in sharing his knowledge with others. Says Solomyak, now a Professor Emeritus in the Mathematics Department: “Mathematicians are judged not only by their own research, but by the benefit they bring to the scientific community, by the kinds of problems one can discuss with them. Zalgaller is exceptional in that you can fruitfully discuss with him a huge portion of mathematics.”

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