Alexander Markowich Ostrowski
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Alexander Markowich Ostrowski
Alexander Markowich Ostrowski ( uk, Олександр Маркович Островський; russian: Алекса́ндр Ма́ркович Остро́вский; 25 September 1893, in Kiev, Russian Empire – 20 November 1986, in Montagnola, Lugano, Switzerland) was a mathematician. His father Mark having been a merchant, Alexander Ostrowski attended the Kiev College of Commerce, not a high school, and thus had an insufficient qualification to be admitted to university. However, his talent did not remain undetected: Ostrowski's mentor, Dmitry Grave, wrote to Landau and Hensel for help. Subsequently, Ostrowski began to study mathematics at Marburg University under Hensel's supervision in 1912. During World War I he was interned, but thanks to the intervention of Hensel, the restrictions on his movements were eased somewhat, and he was allowed to use the university library. After the war ended Ostrowski moved to Göttingen where he wrote his doctoral dissertation a ...
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Kiev
Kyiv, also spelled Kiev, is the capital and most populous city of Ukraine. It is in north-central Ukraine along the Dnieper, Dnieper River. As of 1 January 2021, its population was 2,962,180, making Kyiv the List of European cities by population within city limits, seventh-most populous city in Europe. Kyiv is an important industrial, scientific, educational, and cultural center in Eastern Europe. It is home to many High tech, high-tech industries, higher education institutions, and historical landmarks. The city has an extensive system of Transport in Kyiv, public transport and infrastructure, including the Kyiv Metro. The city's name is said to derive from the name of Kyi, one of its four legendary founders. During History of Kyiv, its history, Kyiv, one of the oldest cities in Eastern Europe, passed through several stages of prominence and obscurity. The city probably existed as a commercial center as early as the 5th century. A Slavs, Slavic settlement on the great trade ...
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Göttingen
Göttingen (, , ; nds, Chöttingen) is a college town, university city in Lower Saxony, central Germany, the Capital (political), capital of Göttingen (district), the eponymous district. The River Leine runs through it. At the end of 2019, the population was 118,911. General information The origins of Göttingen lay in a village called ''Gutingi, ''first mentioned in a document in 953 AD. The city was founded northwest of this village, between 1150 and 1200 AD, and adopted its name. In Middle Ages, medieval times the city was a member of the Hanseatic League and hence a wealthy town. Today, Göttingen is famous for its old university (''Georgia Augusta'', or University of Göttingen, "Georg-August-Universität"), which was founded in 1734 (first classes in 1737) and became the most visited university of Europe. In 1837, seven professors protested against the absolute sovereignty of the House of Hanover, kings of Kingdom of Hanover, Hanover; they lost their positions, but be ...
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Numerical Analysts
Numerical may refer to: * Number * Numerical digit * Numerical analysis Numerical analysis is the study of algorithms that use numerical approximation (as opposed to symbolic computation, symbolic manipulations) for the problems of mathematical analysis (as distinguished from discrete mathematics). It is the study of ...
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Mathematical Analysts
Mathematics is an area of knowledge that includes the topics of numbers, formulas and related structures, shapes and the spaces in which they are contained, and quantities and their changes. These topics are represented in modern mathematics with the major subdisciplines of number theory, algebra, geometry, and analysis, respectively. There is no general consensus among mathematicians about a common definition for their academic discipline. Most mathematical activity involves the discovery of properties of abstract objects and the use of pure reason to prove them. These objects consist of either abstractions from nature orin modern mathematicsentities that are stipulated to have certain properties, called axioms. A ''proof'' consists of a succession of applications of deductive rules to already established results. These results include previously proved theorems, axioms, andin case of abstraction from naturesome basic properties that are considered true starting points of t ...
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Operator Theorists
Operator may refer to: Mathematics * A symbol indicating a mathematical operation * Logical operator or logical connective in mathematical logic * Operator (mathematics), mapping that acts on elements of a space to produce elements of another space, e.g.: ** Linear operator ** Differential operator ** Integral operator (other) Computers * Computer operator, an occupation * Operator (computer programming), a type of computer program function * Operator (extension), an extension for the Firefox web browser, for reading microformats * Ableton Operator, a software synthesizer developed by Ableton Science * Operator (biology), a segment of DNA regulating the activity of genes * Operator (linguistics), a special category including wh- interrogatives * Operator (physics), mathematical operators in quantum physics Music * Operator (band), an American hard rock band * Operators, a synth pop band led by Dan Boeckner * ''Operator'' (album), a 2016 album by Mstrkrft * "Oper ...
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Functional Analysts
Functional may refer to: * Movements in architecture: ** Functionalism (architecture) ** Form follows function * Functional group, combination of atoms within molecules * Medical conditions without currently visible organic basis: ** Functional symptom ** Functional disorder * Functional classification for roads * Functional organization * Functional training In mathematics * Functional (mathematics), a term applied to certain scalar-valued functions in mathematics and computer science ** Functional analysis ** Linear functional, a type of functional often simply called a functional in the context of functional analysis * Higher-order function, also called a functional, a function that takes other functions as arguments In computer science, software engineering * (C++), a header file in the C++ Standard Library * Functional design, a paradigm used to simplify the design of hardware and software devices * Functional model, a structured representation of functions, activities ...
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Ostrowski Prize
The Ostrowski Prize is a mathematics award given every odd year for outstanding mathematical achievement judged by an international jury from the universities of Basel, Jerusalem, Waterloo and the academies of Denmark and the Netherlands. Alexander Ostrowski, a longtime professor at the University of Basel, left his estate to the foundation in order to establish a prize for outstanding achievements in pure mathematics and the foundations of numerical mathematics. It currently carries a monetary award of 100,000 Swiss francs. Recipients * 1989: Louis de Branges (France / United States) * 1991: Jean Bourgain (Belgium) * 1993: Miklós Laczkovich (Hungary) and Marina Ratner (Russia / United States) * 1995: Andrew J. Wiles (UK) * 1997: Yuri V. Nesterenko (Russia) and Gilles I. Pisier (France) * 1999: Alexander A. Beilinson (Russia / United States) and Helmut H. Hofer (Switzerland / United States) * 2001: Henryk Iwaniec (Poland / United States) and Peter Sar ...
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Ostrowski Numeration
In mathematics, Ostrowski numeration, named after Alexander Ostrowski, is either of two related numeration systems based on continued fractions: a non-standard positional numeral system for integers and a non-integer representation of real numbers. Fix a positive irrational number ''α'' with continued fraction expansion 'a''0; ''a''1, ''a''2, ... Let (''q''''n'') be the sequence of denominators of the convergents ''p''''n''/''q''''n'' to α: so ''q''''n'' = ''a''''n''''q''''n''−1 + ''q''''n''−2. Let ''α''''n'' denote ''T''''n''(''α'') where ''T'' is the Gauss map ''T''(''x'') = , and write ''β''''n'' = (−1)''n''+1 ''α''0 ''α''1 ... ''α''''n'': we have ''β''''n'' = ''a''''n''''β''''n''−1 + ''β''''n''−2. Real number representations Every positive real ''x'' can be written as : x = \sum_^\infty b_n \beta_n \ where the integer coefficients 0 ≤ ''b''''n'' ≤ ''a''''n'' and if ''b''''n'' = ''a''''n'' then ''b''''n''−1 = 0. Integer ...
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Ostrowski–Hadamard Gap Theorem
In mathematics, the Ostrowski–Hadamard gap theorem is a result about the analytic continuation of complex power series whose non-zero terms are of orders that have a suitable "gap" between them. Such a power series is "badly behaved" in the sense that it cannot be extended to be an analytic function anywhere on the boundary of its disc of convergence. The result is named after the mathematicians Alexander Ostrowski and Jacques Hadamard. Statement of the theorem Let 0 < ''p''1 < ''p''2 < ... be a sequence of integer An integer is the number zero (), a positive natural number (, , , etc.) or a negative integer with a minus sign (−1, −2, −3, etc.). The negative numbers are the additive inverses of the corresponding positive numbers. In the language ...s such that, for some ''λ'' > 1 and all ''j'' ∈ N, :\frac > \lambda. Let (''α''''j'')''j''∈N be a sequence of complex numbers such that the ...
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Ostrowski's Theorem
In number theory, Ostrowski's theorem, due to Alexander Ostrowski (1916), states that every non-trivial absolute value on the rational numbers \Q is equivalent to either the usual real absolute value or a -adic absolute value. Definitions Raising an absolute value to a power less than 1 always results in another absolute value. Two absolute values , \cdot, and , \cdot, _* on a field ''K'' are defined to be equivalent if there exists a real number such that : \forall x \in K: \quad , x, _* = , x, ^c. The trivial absolute value on any field ''K'' is defined to be : , x, _0 := \begin 0 & x = 0, \\ 1 & x \ne 0. \end The real absolute value on the rationals \Q is the standard absolute value on the reals, defined to be : , x, _\infty := \begin x & x \ge 0, \\ -x & x 1, \\ (2) \quad \forall n \in \N \qquad , n, _* &\leq 1. \end It suffices for us to consider the valuation of integers greater than one. For, if we find c \in \R_+ for which , n, _* = , n, ^c_ for all naturals g ...
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