Boris Semyonovich Tsirelson (May 4, 1950 – January 21, 2020) ( he, בוריס סמיונוביץ' צירלסון, russian: Борис Семёнович Цирельсон) was a

Russia Russia (, , ), or the Russian Federation, is a transcontinental country spanning Eastern Europe and Northern Asia. It is the largest country in the world, with its internationally recognised territory covering , and encompassing one-eight ...

n– Israeli mathematician and Professor of Mathematics at Tel Aviv University in Israel, as well as a

Wikipedia editor The Wikipedia community, collectively known colloquially as Wikipedians, is an informal community that volunteers to create and maintain Wikipedia, an online encyclopedia. Since August 2012, the word "Wikipedian" has been an '' Oxford Dicti ...

Biography

Tsirelson was born in

Leningrad Saint Petersburg ( rus, links=no, Санкт-Петербург, a=Ru-Sankt Peterburg Leningrad Petrograd Piter.ogg, r=Sankt-Peterburg, p=ˈsankt pʲɪtʲɪrˈburk), formerly known as Petrograd (1914–1924) and later Leningrad (1924–1991), i ...

to a

Russian Jewish The history of the Jews in Russia and areas historically connected with it goes back at least 1,500 years. Jews in Russia have historically constituted a large religious and ethnic diaspora; the Russian Empire at one time hosted the largest pop ...

family. From his father Simeon's side, he was the great-nephew of rabbi Yehuda Leib Tsirelson, chief rabbi of

Bessarabia Bessarabia (; Gagauz: ''Besarabiya''; Romanian: ''Basarabia''; Ukrainian: ''Бессара́бія'') is a historical region in Eastern Europe, bounded by the Dniester river on the east and the Prut river on the west. About two thirds o ...

from 1918 to 1941, and a prominent posek and Jewish leader. He obtained his Master of Science from the

University of Leningrad Saint Petersburg State University (SPBU; russian: Санкт-Петербургский государственный университет) is a public research university in Saint Petersburg, Russia. Founded in 1724 by a decree of Peter the G ...

and remained there to pursue graduate studies. He obtained his

Ph.D. A Doctor of Philosophy (PhD, Ph.D., or DPhil; Latin: or ') is the most common degree at the highest academic level awarded following a course of study. PhDs are awarded for programs across the whole breadth of academic fields. Because it is ...

in 1975, with thesis "General properties of bounded Gaussian processes and related questions" written under the direction of Ildar Abdulovich Ibragimov. Later, he participated in the

refusenik Refusenik (russian: отказник, otkaznik, ; alternatively spelt refusnik) was an unofficial term for individuals—typically, but not exclusively, Soviet Jews—who were denied permission to emigrate, primarily to Israel, by the author ...

movement, but only received permission to emigrate to Israel in 1991. From then until 2017, he was a professor at Tel-Aviv University. In 1998 he was an Invited Speaker at the International Congress of Mathematicians in Berlin.

Contributions to mathematics

Tsirelson made notable contributions to

probability theory Probability theory is the branch of mathematics concerned with probability. Although there are several different probability interpretations, probability theory treats the concept in a rigorous mathematical manner by expressing it through a set ...

and functional analysis. These include: *

Tsirelson's bound A Tsirelson bound is an upper limit to quantum mechanical correlations between distant events. Given that quantum mechanics violates Bell inequalities (i.e., it cannot be described by a local hidden-variable theory), a natural question to ask is ...

, in quantum mechanics, is an inequality, related to the issue of quantum nonlocality. * Tsirelson space is an example of a reflexive

Banach space In mathematics, more specifically in functional analysis, a Banach space (pronounced ) is a complete normed vector space. Thus, a Banach space is a vector space with a metric that allows the computation of vector length and distance between vect ...

in which neither a ''l^p'' space nor a ''c''₀ space can be embedded. * The Tsirelson drift, a counterexample in the theory of stochastic differential equations. * The

Gaussian isoperimetric inequality In mathematics, the Gaussian isoperimetric inequality, proved by Boris Tsirelson and Vladimir Sudakov, and later independently by Christer Borell, states that among all sets of given Gaussian measure in the ''n''-dimensional Euclidean space, hal ...

(proved by

Vladimir Sudakov Vladimir may refer to: Names * Vladimir (name) for the Bulgarian, Croatian, Czech, Macedonian, Romanian, Russian, Serbian, Slovak and Slovenian spellings of a Slavic name * Uladzimir for the Belarusian version of the name * Volodymyr for the Ukra ...

and Tsirelson, and independently by

Christer Borell Christer or Krister are varieties of the masculine given name Kristian, derived from the Latin name ''Christianus'', which in turn comes from the Greek word ''khristianós'', which means "follower of Christ". The name, written in its two variants C ...

), stating that affine halfspaces are the isoperimetric sets for the

Gaussian measure In mathematics, Gaussian measure is a Borel measure on finite-dimensional Euclidean space R''n'', closely related to the normal distribution in statistics. There is also a generalization to infinite-dimensional spaces. Gaussian measures are nam ...

References

External links

Tsirelson's homepage
at Tel Aviv University
Mourning page
at Tel Aviv University {{DEFAULTSORT:Tsirelson, Boris Mathematicians from Saint Petersburg Israeli mathematicians Israeli Jews Israeli people of Russian-Jewish descent Soviet emigrants to Israel Tel Aviv University faculty 1950 births 2020 deaths Probability theorists Wikipedia people