Dvoretzky's Theorem
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Dvoretzky's Theorem
In mathematics, Dvoretzky's theorem is an important structural theorem about normed vector spaces proved by Aryeh Dvoretzky in the early 1960s, answering a question of Alexander Grothendieck. In essence, it says that every sufficiently high-dimensional normed vector space will have low-dimensional subspaces that are approximately Euclidean. Equivalently, every high-dimensional bounded symmetric convex set has low-dimensional sections that are approximately ellipsoids. A new proof found by Vitali Milman in the 1970s was one of the starting points for the development of asymptotic geometric analysis (also called ''asymptotic functional analysis'' or the ''local theory of Banach spaces''). Original formulations For every natural number ''k'' ∈ N and every ''ε'' > 0 there exists a natural number ''N''(''k'', ''ε'') ∈ N such that if (''X'', ‖·‖) is any normed space of dimension ''N''(''k'', ''ε''), th ...
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Mathematics
Mathematics is a field of study that discovers and organizes methods, Mathematical theory, theories and theorems that are developed and Mathematical proof, proved for the needs of empirical sciences and mathematics itself. There are many areas of mathematics, which include number theory (the study of numbers), algebra (the study of formulas and related structures), geometry (the study of shapes and spaces that contain them), Mathematical analysis, analysis (the study of continuous changes), and set theory (presently used as a foundation for all mathematics). Mathematics involves the description and manipulation of mathematical object, abstract objects that consist of either abstraction (mathematics), abstractions from nature orin modern mathematicspurely abstract entities that are stipulated to have certain properties, called axioms. Mathematics uses pure reason to proof (mathematics), prove properties of objects, a ''proof'' consisting of a succession of applications of in ...
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Concentration Of Measure
In mathematics, concentration of measure (about a median) is a principle that is applied in measure theory, probability and combinatorics, and has consequences for other fields such as Banach space theory. Informally, it states that "A random variable that depends in a Lipschitz way on many independent variables (but not too much on any of them) is essentially constant". The concentration of measure phenomenon was put forth in the early 1970s by Vitali Milman in his works on the local theory of Banach spaces, extending an idea going back to the work of Paul Lévy. It was further developed in the works of Milman and Gromov, Maurey, Pisier, Schechtman, Talagrand, Ledoux, and others. The general setting Let (X, d) be a metric space with a measure \mu on the Borel sets with \mu(X) = 1. Let :\alpha(\varepsilon) = \sup \left\, where :A_\varepsilon = \left\ is the \varepsilon-''extension'' (also called \varepsilon-fattening in the context of the Hausdorff distance) of a s ...
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Banach Spaces
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 is complete in the sense that a Cauchy sequence of vectors always converges to a well-defined limit that is within the space. Banach spaces are named after the Polish mathematician Stefan Banach, who introduced this concept and studied it systematically in 1920–1922 along with Hans Hahn and Eduard Helly. Maurice René Fréchet was the first to use the term "Banach space" and Banach in turn then coined the term " Fréchet space". Banach spaces originally grew out of the study of function spaces by Hilbert, Fréchet, and Riesz earlier in the century. Banach spaces play a central role in functional analysis. In other areas of analysis, the spaces under study are often Banach spaces. Definition A Banach space is a complete normed ...
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Joram Lindenstrauss
Joram Lindenstrauss (; October 28, 1936 – April 29, 2012) was an Israeli mathematician working in functional analysis. He was a professor of mathematics at the Einstein Institute of Mathematics. Biography Joram Lindenstrauss was born in Tel Aviv. He was the only child of a pair of lawyers who immigrated to Israel from Berlin. He began to study mathematics at the Hebrew University of Jerusalem in 1954 while serving in the army. He became a full-time student in 1956 and received his master's degree in 1959. In 1962 Lindenstrauss earned his Ph.D. from the Hebrew University (dissertation: ''Extension of Compact Operators'', advisors: Aryeh Dvoretzky, Branko Grünbaum). He worked as a postdoc at Yale University and the University of Washington in Seattle from 1962 - 1965. He was appointed senior lecturer at the Hebrew University in 1965, associate professor on 1967 and full professor in 1969. He became the Leon H. and Ada G. Miller Memorial Professor of Mathematics in 1985. He ...
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Tadeusz Figiel
Tadeusz Figiel (born 2 July 1948 in Gdańsk) is a Polish mathematician specializing in functional analysis. Biography In 1970 Figiel graduated in mathematics at the University of Warsaw. He received his doctorate in 1972 under the supervision of Aleksander Pełczyński and then habilitated in 1975 with habilitation thesis ''O modułach wypukłości i gładkości'' (On modules of convexity and smoothness) at the (Instytut Matematyczny PAN). There Figiel was appointed in 1983 an associate professor and in 1990 a full professor. He is the head of the Gdańsk Branch of the Polish Academy of Sciences and the editor-in-chief of the journal ''Studia Mathematica''.''Złota księga nauk ekonomicznych, prawnych i ścisłych 2005'' (The Golden Book of Economics, Law and Science 2005), wyd. Mastermedia sp. z o.o. i wyd. Helion, Gliwice 2005, p. 67 Figiel received in 1976 the Stefan Banach Award, in 1988 the of First Degree (together with Zbigniew Ciesielski), in 1989 the , and in 2004 th ...
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Chebyshev Distance
In mathematics, Chebyshev distance (or Tchebychev distance), maximum metric, or L∞ metric is a metric defined on a real coordinate space where the distance between two points is the greatest of their differences along any coordinate dimension. It is named after Pafnuty Chebyshev. It is also known as chessboard distance, since in the game of chess the minimum number of moves needed by a king to go from one square on a chessboard to another equals the Chebyshev distance between the centers of the squares, if the squares have side length one, as represented in 2-D spatial coordinates with axes aligned to the edges of the board. For example, the Chebyshev distance between f6 and e2 equals 4. Definition The Chebyshev distance between two vectors or points ''x'' and ''y'', with standard coordinates x_i and y_i, respectively, is :D(x,y) = \max_i(, x_i -y_i, ).\ This equals the limit of the L''p'' metrics: :D(x,y)=\lim_ \bigg( \sum_^n \left, x_i - y_i \^p \bigg)^, hence it i ...
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Noga Alon
Noga Alon (; born 1956) is an Israeli mathematician and a professor of mathematics at Princeton University noted for his contributions to combinatorics and theoretical computer science, having authored hundreds of papers. Education and career Alon was born in 1956 in Haifa, where he graduated from the Hebrew Reali School in 1974. He graduated summa cum laude from the Technion – Israel Institute of Technology in 1979, earned a master's degree in mathematics in 1980 from Tel Aviv University, and received his Ph.D. in Mathematics at the Hebrew University of Jerusalem in 1983 with the dissertation ''Extremal Problems in Combinatorics'' supervised by Micha Perles. After postdoctoral research at the Massachusetts Institute of Technology he returned to Tel Aviv University as a senior lecturer in 1985, obtained a permanent position as an associate professor there in 1986, and was promoted to full professor in 1988. He was head of the School of Mathematical Science from 1999 to 2001, ...
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Gideon Schechtman
Gideon Schechtman (; born 14 February 1947) is an Israeli mathematician and professor of mathematics at the Weizmann Institute of Science. Academic career Schechtman received his Ph.D. in mathematics from the Hebrew University of Jerusalem in 1976 and was a postdoctoral fellow at Ohio State University. Since 1980 he has been affiliated with the Weizmann Institute, where he became emeritus professor in 2017. His research focuses predominantly on functional analysis and the geometry of Banach spaces. Schechtman is an editor of the Israel Journal of Mathematics '' Israel Journal of Mathematics'' is a peer-reviewed mathematics journal published by the Hebrew University of Jerusalem ( Magnes Press). History Founded in 1963, as a continuation of the ''Bulletin of the Research Council of Israel'' (Section .... References {{DEFAULTSORT:Schechtman, Gideon 1947 births Functional analysts Einstein Institute of Mathematics alumni Israeli Jews Israeli mathematicians Academic s ...
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Israel Journal Of Mathematics
'' Israel Journal of Mathematics'' is a peer-reviewed mathematics journal published by the Hebrew University of Jerusalem ( Magnes Press). History Founded in 1963, as a continuation of the ''Bulletin of the Research Council of Israel'' (Section F), the journal publishes articles on all areas of mathematics. The journal is indexed by ''Mathematical Reviews'' and Zentralblatt MATH. Its 2009 MCQ was 0.70, and its 2009 impact factor The impact factor (IF) or journal impact factor (JIF) of an academic journal is a type of journal ranking. Journals with higher impact factor values are considered more prestigious or important within their field. The Impact Factor of a journa ... was 0.754. External links * Mathematics journals Academic journals established in 1963 Academic journals of Israel English-language journals Bimonthly journals Hebrew University of Jerusalem {{math-journal-stub ...
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Yehoram Gordon
Jehoram (meaning "Jehovah is exalted" in Biblical Hebrew) was the name of several individuals in the Tanakh. The female version of this name is Athaliah. *The son of Toi, King of Hamath who was sent by his father to congratulate David on the occasion of his victory over Hadadezer (2 Samuel 8:10) *Jehoram of Israel or Joram, King of Israel (ruled c. 852/49–842/41) *Jehoram of Judah or Joram, King of Judah (ruled c. 849/48–842/41) *A Levite of the family of Gershom (1 Chronicles 26:25) *A priest sent by Jehoshaphat to instruct the people in Judah (2 Chronicles 17:8) In modern days, it is also the name of: *Yehoram Gaon Yehoram Gaon (; born December 28, 1939) is an Israeli singer, actor, director, comedian, producer, TV and radio host, and public figure. He has also written and edited books on Israeli culture. The son of Sephardic Jewish parents—a Bosnian f ...
(born 1939), Israeli singer and actor {{disambiguation, hndis ...
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Dvoretzky Dimension
Dvoretzky is a surname. Notable people with the surname include: * Aryeh Dvoretzky (1916–2008), Russian-born Israeli mathematician, eighth president of the Weizmann Institute of Science * Moshe Dvoretzky (1922–1988), Bulgarian actor See also * Dvoretzky's theorem In mathematics, Dvoretzky's theorem is an important structural theorem about normed vector spaces proved by Aryeh Dvoretzky in the early 1960s, answering a question of Alexander Grothendieck. In essence, it says that every sufficiently high-dimensi ...
{{Surname ...
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Unit Sphere
In mathematics, a unit sphere is a sphere of unit radius: the locus (mathematics), set of points at Euclidean distance 1 from some center (geometry), center point in three-dimensional space. More generally, the ''unit -sphere'' is an n-sphere, -sphere of unit radius in -dimensional Euclidean space; the unit circle is a special case, the unit -sphere in the Euclidean plane, plane. An (Open set, open) unit ball is the region inside of a unit sphere, the set of points of distance less than 1 from the center. A sphere or ball with unit radius and center at the origin (mathematics), origin of the space is called ''the'' unit sphere or ''the'' unit ball. Any arbitrary sphere can be transformed to the unit sphere by a combination of translation (geometry), translation and scaling (geometry), scaling, so the study of spheres in general can often be reduced to the study of the unit sphere. The unit sphere is often used as a model for spherical geometry because it has constant sectional cu ...
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