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Ernst Leonard Lindelöf
Ernst Leonard Lindelöf (; 7 March 1870 – 4 June 1946) was a Finnish mathematician, who made contributions in real analysis, complex analysis and topology. Lindelöf spaces are named after him. He was the son of mathematician Lorenz Leonard Lindelöf and brother of the philologist . Biography Lindelöf studied at the University of Helsinki, where he completed his PhD in 1893, became a docent in 1895 and professor of Mathematics in 1903. He was a member of the Finnish Society of Sciences and Letters. In addition to working in a number of different mathematical domains including complex analysis, conformal mappings, topology, ordinary differential equations and the gamma function, Lindelöf promoted the study of the history of Finnish mathematics. He is known for the Picard–Lindelöf theorem on differential equations and the Phragmén–Lindelöf principle, one of several refinements of the maximum modulus principle that he proved in complex function theory. He was the P ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Helsinki
Helsinki ( or ; ; sv, Helsingfors, ) is the Capital city, capital, primate city, primate, and List of cities and towns in Finland, most populous city of Finland. Located on the shore of the Gulf of Finland, it is the seat of the region of Uusimaa in southern Finland, and has a population of . The Helsinki urban area, city's urban area has a population of , making it by far the List of urban areas in Finland by population, most populous urban area in Finland as well as the country's most important center for politics, education, finance, culture, and research; while Tampere in the Pirkanmaa region, located to the north from Helsinki, is the second largest urban area in Finland. Helsinki is located north of Tallinn, Estonia, east of Stockholm, Sweden, and west of Saint Petersburg, Russia. It has History of Helsinki, close historical ties with these three cities. Together with the cities of Espoo, Vantaa, and Kauniainen (and surrounding commuter towns, including the eastern ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lorenz Leonard Lindelöf
Lorenz Leonard Lindelöf (13 November 1827, Karvia, Finland – 3 March 1908, Helsinki) was a Finnish mathematician and astronomer. Biography Lindelöf came from a poor family. He learned German and French and studied astronomy and mathematics at the University of Helsinki. He initially specialized in astronomy at the graduate level and was at Pulkovo Observatory in 1855–1856. After his completion of his PhD (Promotierung), Lindelöf from 1857 to 1874 held the professorial chair of mathematics in Helsinki and from 1869 to 1872 was the rector of the university. He then resigned his professorial chair in favor of Mittag-Leffler and turned to politics. Lindelöf was from 1874 to 1902 minister of state education in Finland and also did actuarial work for Kaleva Mutual Insurance Company. In 1883 he was knighted and in 1888 was a member of the State Council. He was in the Finnish Parliament, served on many committees and was in 1900 District Marshal. Lindelöf published papers on mi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1946 Deaths
Events January * January 6 - The 1946 North Vietnamese parliamentary election, first general election ever in Vietnam is held. * January 7 – The Allies recognize the Austrian republic with its 1937 borders, and divide the country into four Allied-occupied Austria, occupation zones. * January 10 ** The first meeting of the United Nations is held, at Methodist Central Hall Westminster in London. ** ''Project Diana'' bounces radar waves off the Moon, measuring the exact distance between the Earth and the Moon, and proves that communication is possible between Earth and outer space, effectively opening the Space Age. * January 11 - Enver Hoxha declares the People's Republic of Albania, with himself as prime minister of Albania, prime minister. * January 16 – Charles de Gaulle resigns as head of the Provisional Government of the French Republic, French provisional government. * January 17 - The United Nations Security Council holds its first session, at Church House, Westmin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1870 Births
Year 187 ( CLXXXVII) was a common year starting on Sunday (link will display the full calendar) of the Julian calendar. At the time, it was known as the Year of the Consulship of Quintius and Aelianus (or, less frequently, year 940 ''Ab urbe condita''). The denomination 187 for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years. Events By place Roman Empire * Septimius Severus marries Julia Domna (age 17), a Syrian princess, at Lugdunum (modern-day Lyon). She is the youngest daughter of high-priest Julius Bassianus – a descendant of the Royal House of Emesa. Her elder sister is Julia Maesa. * Clodius Albinus defeats the Chatti, a highly organized German tribe that controlled the area that includes the Black Forest. By topic Religion * Olympianus succeeds Pertinax as bishop of Byzantium (until 198). Births * Cao Pi, Chinese emperor of the Cao Wei stat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acta Mathematica
''Acta Mathematica'' is a peer-reviewed open-access scientific journal covering research in all fields of mathematics. According to Cédric Villani, this journal is "considered by many to be the most prestigious of all mathematical research journals".. According to the ''Journal Citation Reports'', the journal has a 2020 impact factor of 4.273, ranking it 5th out of 330 journals in the category "Mathematics". Publication history The journal was established by Gösta Mittag-Leffler in 1882 and is published by Institut Mittag-Leffler, a research institute for mathematics belonging to the Royal Swedish Academy of Sciences. The journal was printed and distributed by Springer from 2006 to 2016. Since 2017, Acta Mathematica has been published electronically and in print by International Press. Its electronic version is open access without publishing fees. Poincaré episode The journal's "most famous episode" (according to Villani) concerns Henri Poincaré, who won a prize offered ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lars Edvard Phragmén
Lars Edvard Phragmén (2 September 1863 Örebro – 13 March 1937) was a Swedish mathematician. The son of a college professor, he studied at Uppsala then Stockholm, graduating from Uppsala in 1889. He became professor at Stockholm in 1892, after Sofia Kovalevskaia. He left Uppsala less than a year after, becoming professor Mittag-Leffler's assistant at Stockholm. In 1884, he provided a new proof of the Cantor-Bendixson theorem. His work focused on elliptic functions and complex analysis. His most famous result is the extension of Liouville's theorem to analytic functions on a sector. A first version was proposed by Phragmén, then improved by the Finnish mathematician Ernst Lindelöf. They jointly published this last version,« ''Sur une extension d'un principe classique de l'analyse et sur quelques propriétés des fonctions monogènes dans le voisinage d'un point singulier'' », Acta Math. 31, 1908 known as the Phragmén–Lindelöf principle. He left the university in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Complex Function Theory
Complex analysis, traditionally known as the theory of functions of a complex variable, is the branch of mathematical analysis that investigates functions of complex numbers. It is helpful in many branches of mathematics, including algebraic geometry, number theory, analytic combinatorics, applied mathematics; as well as in physics, including the branches of hydrodynamics, thermodynamics, and particularly quantum mechanics. By extension, use of complex analysis also has applications in engineering fields such as nuclear, aerospace, mechanical and electrical engineering. As a differentiable function of a complex variable is equal to its Taylor series (that is, it is analytic), complex analysis is particularly concerned with analytic functions of a complex variable (that is, holomorphic functions). History Complex analysis is one of the classical branches in mathematics, with roots in the 18th century and just prior. Important mathematicians associated with com ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maximum Modulus Principle
In mathematics, the maximum modulus principle in complex analysis states that if ''f'' is a holomorphic function, then the modulus , ''f'' , cannot exhibit a strict local maximum that is properly within the domain of ''f''. In other words, either ''f'' is locally a constant function, or, for any point ''z''0 inside the domain of ''f'' there exist other points arbitrarily close to ''z''0 at which , ''f'' , takes larger values. Formal statement Let ''f'' be a holomorphic function on some connected open subset ''D'' of the complex plane ℂ and taking complex values. If ''z''0 is a point in ''D'' such that :, f(z_0), \ge , f(z), for all ''z'' in some neighborhood of ''z''0, then ''f'' is constant on ''D''. This statement can be viewed as a special case of the open mapping theorem, which states that a nonconstant holomorphic function maps open sets to open sets: If , ''f'', attains a local maximum at ''z'', then the image of a sufficiently small open neighborhood of ''z'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gamma Function
In mathematics, the gamma function (represented by , the capital letter gamma from the Greek alphabet) is one commonly used extension of the factorial function to complex numbers. The gamma function is defined for all complex numbers except the non-positive integers. For every positive integer , \Gamma(n) = (n-1)!\,. Derived by Daniel Bernoulli, for complex numbers with a positive real part, the gamma function is defined via a convergent improper integral: \Gamma(z) = \int_0^\infty t^ e^\,dt, \ \qquad \Re(z) > 0\,. The gamma function then is defined as the analytic continuation of this integral function to a meromorphic function that is holomorphic in the whole complex plane except zero and the negative integers, where the function has simple poles. The gamma function has no zeroes, so the reciprocal gamma function is an entire function. In fact, the gamma function corresponds to the Mellin transform of the negative exponential function: \Gamma(z) = \mathcal M ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ordinary Differential Equation
In mathematics, an ordinary differential equation (ODE) is a differential equation whose unknown(s) consists of one (or more) function(s) of one variable and involves the derivatives of those functions. The term ''ordinary'' is used in contrast with the term partial differential equation which may be with respect to ''more than'' one independent variable. Differential equations A linear differential equation is a differential equation that is defined by a linear polynomial in the unknown function and its derivatives, that is an equation of the form :a_0(x)y +a_1(x)y' + a_2(x)y'' +\cdots +a_n(x)y^+b(x)=0, where , ..., and are arbitrary differentiable functions that do not need to be linear, and are the successive derivatives of the unknown function of the variable . Among ordinary differential equations, linear differential equations play a prominent role for several reasons. Most elementary and special functions that are encountered in physics and applied mathem ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Conformal Mapping
In mathematics, a conformal map is a function that locally preserves angles, but not necessarily lengths. More formally, let U and V be open subsets of \mathbb^n. A function f:U\to V is called conformal (or angle-preserving) at a point u_0\in U if it preserves angles between directed curves through u_0, as well as preserving orientation. Conformal maps preserve both angles and the shapes of infinitesimally small figures, but not necessarily their size or curvature. The conformal property may be described in terms of the Jacobian derivative matrix of a coordinate transformation. The transformation is conformal whenever the Jacobian at each point is a positive scalar times a rotation matrix (orthogonal with determinant one). Some authors define conformality to include orientation-reversing mappings whose Jacobians can be written as any scalar times any orthogonal matrix. For mappings in two dimensions, the (orientation-preserving) conformal mappings are precisely the locall ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Finnish Society Of Sciences And Letters
The Finnish Society of Sciences and Letters is a Finnish academy for natural sciences, social sciences and humanities. It is known in Latin as Societas Scientiarum Fennica, in Swedish as Finska Vetenskaps-Societeten, and in Finnish as Suomen Tiedeseura. It is a bilingual (Swedish and Finnish) science academy and the oldest of the four science academies in Finland. The society was founded in 1838 and is based in Helsinki. It has a total of 120 full ordinary Finnish members, excluding members who have reached the age of 67 (a member who reaches the age of 67 retains the rights as a member but leaves his or her chair open for election of a new member), and about 120 foreign members. It is divided into four sections: I: mathematics and physics, II: biosciences, III: humanities, and IV: social sciences. The society publishes a yearbook, ''Sphinx'', and the book series ''Commentationes Humanarum Litterarum'', ''Commentationes Scientiarum Socialium'', ''Bidrag till kännedom av Finlan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
