Israel Gelfand

Template:Short description Template:Distinguish Template:Use dmy dates Template:Family name hatnote

Template:Infobox scientist Israel Moiseevich Gelfand, also written Israïl Moyseyovich Gel'fand, or Izrail M. Gelfand (Template:Langx, Template:Langx, Template:Langx; Template:OldStyleDate – 5 October 2009) was a prominent Soviet and American mathematician, one of the greatest mathematicians of the 20th century, biologist, teacher and organizer of mathematical education. He made significant contributions to many branches of mathematics, including group theory, representation theory and functional analysis. The recipient of many awards, including the Order of Lenin and the first Wolf Prize, he was a Foreign Fellow of the Royal Society and professor at Moscow State University and, after immigrating to the United States shortly before his 76th birthday, at Rutgers University. Gelfand is also a 1994 MacArthur Fellow.

His legacy continues through his students, who include Endre Szemerédi, Alexandre Kirillov, Edward Frenkel,<ref>Template:Cite book</ref> Joseph Bernstein, David Kazhdan, as well as his own son, Sergei Gelfand.

Early yearsEdit

A native of Kherson Governorate, Russian Empire (now, Odesa Oblast, Ukraine), Gelfand was born into a Jewish family in the small southern Ukrainian town of Okny. According to his own account, Gelfand was expelled from high school under the Soviets because his father had been a mill owner. Bypassing both high school and college, he proceeded to postgraduate study at the age of 19 at Moscow State University, where his advisor was the preeminent mathematician Andrei Kolmogorov.<ref name="Telegraph">Template:Cite news</ref> He received his PhD in 1935.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

Gelfand immigrated to the United States in 1989.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

WorkEdit

Gelfand is known for many developments including:

the book Calculus of Variations (1963), which he co-authored with Sergei Fomin;
Gelfand's formula, which expresses the spectral radius as a limit of matrix norms.
the Gelfand representation in Banach algebra theory;
the Gelfand–Mazur theorem in Banach algebra theory;
the Gelfand–Naimark theorem;
the Gelfand–Naimark–Segal construction;
Gelfand–Shilov spaces;
the Gelfand–Pettis integral;
the representation theory of the complex classical Lie groups;
contributions to the theory of Verma modules in the representation theory of semisimple Lie algebras (with I. N. Bernstein and S. I. Gelfand);
contributions to distribution theory and measures on infinite-dimensional spaces;<ref>Template:Citation</ref>
the first observation of the connection of automorphic forms with representations (with Sergei Fomin);
conjectures about the Atiyah–Singer index theorem;
ordinary differential equations (Gelfand–Levitan theory);
work on calculus of variations and soliton theory (Gelfand–Dikii equations);
contributions to the philosophy of cusp forms;
Gelfand–Fuchs cohomology of Lie algebras;
Gelfand–Kirillov dimension;
integral geometry;
combinatorial definition of the Pontryagin class;
Coxeter functors;
general hypergeometric functions;
Gelfand–Tsetlin patterns;
Gelfand–Lokutsievski method;
and many other results, particularly in the representation theory of classical groups.

Gelfand ran a seminar at Moscow State University from 1943[1] until May 1989 (when it continued at Rutgers University), which covered a wide range of topics and was an important school for many mathematicians.<ref>M.I. Vishik, G.E. Shilov, I.M. Gel'fand Seminar on Functional Analysis and Mathematical Physics in Moscow State University (in Russian), Uspekhi Mat. Nauk, 13:2(80) (1958), 253–263.</ref><ref>Конспекты М.А. Шубина с семинаров И.М. Гельфанда</ref><ref>Александр Бейлинсон, И. М. Гельфанд и его семинар (I. M. Gelfand and his seminar — a presence)</ref>

Influence outside mathematicsEdit

The Gelfand–Tsetlin (also spelled Zetlin) basis is a widely used tool in theoretical physics and the result of Gelfand's work on the representation theory of the unitary group and Lie groups in general.

Gelfand also published works on biology and medicine.<ref>ru:Гельфанд, Израиль Моисеевич</ref> For a long time he took an interest in cell biology and organized a research seminar on the subject.<ref>V.I. Agol, Notes about I.M. Gelfand’s Seminar, Russian Journal Developmental Biology, Volume 39 (2008), Number 6, 367–368.</ref><ref>L.V. Beloussov, Short notes about Gelfand’s Seminar, Russian Journal Developmental Biology, Volume 39 (2008), Number 6, 369–370.</ref>

He worked extensively in mathematics education, particularly with correspondence education. In 1994, he was awarded a MacArthur Fellowship for this work.

Personal lifeEdit

Gelfand was married to Zorya Shapiro, and their two sons, Sergei and Vladimir both live in the United States. The third son, Aleksandr, died of leukemia. Following the divorce from his first wife, Gelfand married his second wife, Tatiana; together they had a daughter, Tatiana. The family also includes four grandchildren and three great-grandchildren.<ref>Chang, Kenneth. "Israel Gelfand, Math Giant, Dies at 96", The New York Times (October 7, 2009)</ref><ref>Template:Cite news</ref> Memories about I. Gelfand are collected at a dedicated website handled by his family.<ref>http://israelmgelfand.com/ site dedicated to Israel M. Gelfand</ref>

Gelfand was an advocate of animal rights.<ref name="Interview">"Interview with Israel Gelfand and Tatiana V. Gelfand". vita.org.ru. Retrieved 25 February 2023.</ref> He became a vegetarian in 1994 and vegan in 2000.<ref name="Interview"/><ref>"Israel Gelfand". telegraph.co.uk. Retrieved 25 February 2023.</ref>

Honors and awardsEdit

Gelfand held several honorary degrees and was awarded the Order of Lenin three times for his research. In 1977 he was elected a Foreign Member of the Royal Society. He won the Wolf Prize in 1978, Kyoto Prize in 1989 and MacArthur Foundation Fellowship in 1994. He held the presidency of the Moscow Mathematical Society between 1968 and 1970, and was elected a foreign member of the U.S. National Academy of Science, the American Academy of Arts and Sciences, the Royal Irish Academy, the American Mathematical Society and the London Mathematical Society.

In an October 2003 article in The New York Times, written on the occasion of his 90th birthday, Gelfand is described as a scholar who is considered "among the greatest mathematicians of the 20th century",<ref>Kochman, Marilyn. "In Person: An Equation for Success", The New York Times (October 5, 2003)</ref> having exerted a tremendous influence on the field both through his own works and those of his students.