Boris Semyonovich Tsirelson (, ; May 4, 1950 – January 21, 2020) was a

Russia Russia, or the Russian Federation, is a country spanning Eastern Europe and North Asia. It is the list of countries and dependencies by area, largest country in the world, and extends across Time in Russia, eleven time zones, sharing Borders ...

n–

Israel Israel, officially the State of Israel, is a country in West Asia. It Borders of Israel, shares borders with Lebanon to the north, Syria to the north-east, Jordan to the east, Egypt to the south-west, and the Mediterranean Sea to the west. Isr ...

mathematician A mathematician is someone who uses an extensive knowledge of mathematics in their work, typically to solve mathematical problems. Mathematicians are concerned with numbers, data, quantity, mathematical structure, structure, space, Mathematica ...

and Professor of Mathematics at

Tel Aviv University Tel Aviv University (TAU) is a Public university, public research university in Tel Aviv, Israel. With over 30,000 students, it is the largest university in the country. Located in northwest Tel Aviv, the university is the center of teaching and ...

, as well as a Wikipedia editor.

Biography

Tsirelson was born in

Leningrad Saint Petersburg, formerly known as Petrograd and later Leningrad, is the List of cities and towns in Russia by population, second-largest city in Russia after Moscow. It is situated on the Neva, River Neva, at the head of the Gulf of Finland ...

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 po ...

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

Yehuda Leib Tsirelson Yehuda Leib Tsirelson (1859 in Kozelets, Chernihiv Oblast – 1941 in Kishinev, Soviet Union) was the Chief Rabbi of Bessarabia, a member of the Romanian parliament, and a prominent Jewish leader and posek. Biography Yehuda Leib Tsirelson was ...

, chief rabbi of

Bessarabia Bessarabia () 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 of Bessarabia lies within modern-day Moldova, with the Budjak region covering the southern coa ...

from 1918 to 1941, and a prominent

posek In Jewish law, a ''posek'' ( , pl. ''poskim'', ) is a legal scholar who determines the application of ''halakha'', the Jewish religious laws derived from the written and Oral Torah, in cases of Jewish law where previous authorities are incon ...

and Jewish leader. He obtained his Master of Science from the University of Leningrad and remained there to pursue graduate studies. He obtained his

Ph.D. A Doctor of Philosophy (PhD, DPhil; or ) is a terminal degree that usually denotes the highest level of academic achievement in a given discipline and is awarded following a course of graduate study and original research. The name of the deg ...

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 (, ; alternatively spelled refusnik) was an unofficial term for individuals—typically, but not exclusively, Soviet Jews—who were denied permission to emigrate, primarily to Israel, by the authorities of the Soviet Union and oth ...

movement, but only received permission to immigrate to Israel in 1991. From then until 2017, he was a professor at

Tel-Aviv University Tel Aviv University (TAU) is a Public university, public research university in Tel Aviv, Israel. With over 30,000 students, it is the largest university in the country. Located in northwest Tel Aviv, the university is the center of teaching and ...

. He has also worked on fault-tolerant

cellular automaton A cellular automaton (pl. cellular automata, abbrev. CA) is a discrete model of computation studied in automata theory. Cellular automata are also called cellular spaces, tessellation automata, homogeneous structures, cellular structures, tessel ...

. In 1998 he was an Invited Speaker at the

International Congress of Mathematicians The International Congress of Mathematicians (ICM) is the largest conference for the topic of mathematics. It meets once every four years, hosted by the International Mathematical Union (IMU). The Fields Medals, the IMU Abacus Medal (known before ...

in Berlin.

Contributions to mathematics

Tsirelson made notable contributions to

probability theory Probability theory or probability calculus 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 expre ...

and

functional analysis Functional analysis is a branch of mathematical analysis, the core of which is formed by the study of vector spaces endowed with some kind of limit-related structure (for example, Inner product space#Definition, inner product, Norm (mathematics ...

. 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 h ...

, in

quantum mechanics Quantum mechanics is the fundamental physical Scientific theory, theory that describes the behavior of matter and of light; its unusual characteristics typically occur at and below the scale of atoms. Reprinted, Addison-Wesley, 1989, It is ...

, is an inequality, related to the issue of

quantum nonlocality In theoretical physics, quantum nonlocality refers to the phenomenon by which the measurement statistics of a multipartite quantum system do not allow an interpretation with local realism. Quantum nonlocality has been experimentally verified unde ...

. *

Tsirelson space In mathematics, especially in functional analysis, the Tsirelson space is the first example of a Banach space in which neither an ℓ ''p'' space nor a ''c''0 space can be embedded. The Tsirelson space is reflexive. It was introduced by B. ...

is an example of a reflexive

Banach space In mathematics, more specifically in functional analysis, a Banach space (, ) 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 vectors and ...

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

stochastic differential equations A stochastic differential equation (SDE) is a differential equation in which one or more of the terms is a stochastic process, resulting in a solution which is also a stochastic process. SDEs have many applications throughout pure mathematics and ...

, is an SDE which has a weak solution but no strong solution. * The

Gaussian isoperimetric inequality Carl Friedrich Gauss (1777–1855) is the eponym of all of the topics listed below. There are over 100 topics all named after this German mathematician and scientist, all in the fields of mathematics, physics, and astronomy. The English eponymo ...

(proved by Vladimir Sudakov and Tsirelson, and independently by Christer Borell), 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 \mathbb^n, closely related to the normal distribution in statistics. There is also a generalization to infinite-dimensional spaces. Gaussian measures are na ...

Death

Tsirelson died on January 21, 2020, at the age of 69.

References

External links

Tsirelson's homepage
at

Mourning page
at

{{DEFAULTSORT:Tsirelson, Boris Mathematicians from Saint Petersburg Israeli mathematicians Israeli Jews Israeli people of Russian-Jewish descent Soviet emigrants to Israel Academic staff of Tel Aviv University 1950 births 2020 deaths Probability theorists Wikipedia people