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Henry Wallman
Henry "Hank" Wallman (1915Biography of Wallman at the (in Swedish).–1992) was an American mathematician, known for his work in , , , and |
Chalmers University Of Technology
Chalmers University of Technology ( sv, Chalmers tekniska högskola, often shortened to Chalmers) is a Swedish university located in Gothenburg that conducts research and education in technology and natural sciences at a high international level. The university has approximately 3100 employees and 10,000 students, and offers education in engineering, science, shipping, architecture and other management areas. Chalmers is coordinating the Graphene Flagship, the European Union's biggest research initiative to bring graphene innovation out of the lab and into commercial applications, and leading the development of a Swedish quantum computer. History The university was founded in 1829 following a donation by William Chalmers, a director of the Swedish East India Company. He donated part of his fortune for the establishment of an "industrial school". Chalmers is one of only three universities in Sweden which are named after a person, the other two being Karolinska Institutet and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Swedish Royal Academies
The Royal Academies are independent organizations, founded on Royal command, that act to promote the arts, culture, and science in Sweden. The Swedish Academy and Academy of Sciences are also responsible for the selection of Nobel Prize laureates in Literature, Physics, Chemistry, and the Prize in Economic Sciences. Also included in the Royal Academies are scientific societies that were granted Royal Charters. Arts and culture *Swedish Academy (''Svenska Akademien''), 1786 *Royal Swedish Academy of Fine Arts (''Kungl. Akademien för de Fria konsterna''), 1773 *Royal Swedish Academy of Music (''Kungl. Musikaliska Akademien''), 1771 * Royal Swedish Academy of Letters, History and Antiquities (''Kungl. Vitterhets-, Historie- och Antikvitetsakademien''), 1753 Sciences *Royal Swedish Academy of Sciences (''Kungl. Vetenskapsakademien''), 1739 *Royal Swedish Academy of Engineering Sciences (''Kungl. Ingenjörsvetenskapsakademien''), 1919 *Royal Swedish Academy of Agriculture and Forestry ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Central Limit Theorem
In probability theory, the central limit theorem (CLT) establishes that, in many situations, when independent random variables are summed up, their properly normalized sum tends toward a normal distribution even if the original variables themselves are not normally distributed. The theorem is a key concept in probability theory because it implies that probabilistic and statistical methods that work for normal distributions can be applicable to many problems involving other types of distributions. This theorem has seen many changes during the formal development of probability theory. Previous versions of the theorem date back to 1811, but in its modern general form, this fundamental result in probability theory was precisely stated as late as 1920, thereby serving as a bridge between classical and modern probability theory. If X_1, X_2, \dots, X_n, \dots are random samples drawn from a population with overall mean \mu and finite variance and if \bar_n is the sample mean of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
New York City
New York, often called New York City or NYC, is the List of United States cities by population, most populous city in the United States. With a 2020 population of 8,804,190 distributed over , New York City is also the List of United States cities by population density, most densely populated major city in the United States, and is more than twice as populous as second-place Los Angeles. New York City lies at the southern tip of New York (state), New York State, and constitutes the geographical and demographic center of both the Northeast megalopolis and the New York metropolitan area, the largest metropolitan area in the world by urban area, urban landmass. With over 20.1 million people in its metropolitan statistical area and 23.5 million in its combined statistical area as of 2020, New York is one of the world's most populous Megacity, megacities, and over 58 million people live within of the city. New York City is a global city, global Culture of New ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amplifier
An amplifier, electronic amplifier or (informally) amp is an electronic device that can increase the magnitude of a signal (a time-varying voltage or current). It may increase the power significantly, or its main effect may be to boost the voltage or current (power, voltage or current amplifier). It is a two-port electronic circuit that uses electric power from a power supply to increase the amplitude of a signal applied to its input terminals, producing a greater amplitude signal at its output. The ratio of output to input voltage, current, or power is termed gain (voltage, current, or power gain). An amplifier, by definition has gain greater than unity (if the gain is less than unity, the device is an attenuator). An amplifier can either be a separate piece of equipment or an electrical circuit contained within another device. Amplification is fundamental to modern electronics, and amplifiers are widely used in almost all electronic equipment. Amplifiers can be categorize ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vacuum Tube
A vacuum tube, electron tube, valve (British usage), or tube (North America), is a device that controls electric current flow in a high vacuum between electrodes to which an electric voltage, potential difference has been applied. The type known as a thermionic tube or thermionic valve utilizes thermionic emission of electrons from a hot cathode for fundamental electronic functions such as signal amplifier, amplification and current rectifier, rectification. Non-thermionic types such as a vacuum phototube, however, achieve electron emission through the photoelectric effect, and are used for such purposes as the detection of light intensities. In both types, the electrons are accelerated from the cathode to the anode by the electric field in the tube. The simplest vacuum tube, the diode (i.e. Fleming valve), invented in 1904 by John Ambrose Fleming, contains only a heated electron-emitting cathode and an anode. Electrons can only flow in one direction through the device—fro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radio
Radio is the technology of signaling and communicating using radio waves. Radio waves are electromagnetic waves of frequency between 30 hertz (Hz) and 300 gigahertz (GHz). They are generated by an electronic device called a transmitter connected to an antenna which radiates the waves, and received by another antenna connected to a radio receiver. Radio is very widely used in modern technology, in radio communication, radar, radio navigation, remote control, remote sensing, and other applications. In radio communication, used in radio and television broadcasting, cell phones, two-way radios, wireless networking, and satellite communication, among numerous other uses, radio waves are used to carry information across space from a transmitter to a receiver, by modulating the radio signal (impressing an information signal on the radio wave by varying some aspect of the wave) in the transmitter. In radar, used to locate and track objects like aircraft, ships, spacecraf ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hassler Whitney
Hassler Whitney (March 23, 1907 – May 10, 1989) was an American mathematician. He was one of the founders of singularity theory, and did foundational work in manifolds, embeddings, immersions, characteristic classes, and geometric integration theory. Biography Life Hassler Whitney was born on March 23, 1907, in New York City, where his father Edward Baldwin Whitney was the First District New York Supreme Court judge. His mother, A. Josepha Newcomb Whitney, was an artist and active in politics. He was the paternal nephew of Connecticut Governor and Chief Justice Simeon Eben Baldwin, his paternal grandfather was William Dwight Whitney, professor of Ancient Languages at Yale University, linguist and Sanskrit scholar. Whitney was the great-grandson of Connecticut Governor and US Senator Roger Sherman Baldwin, and the great-great-grandson of American founding father Roger Sherman. His maternal grandparents were astronomer and mathematician Simon Newcomb (1835-1909), a Steeves desce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Science (magazine)
''Science'', also widely referred to as ''Science Magazine'', is the peer-reviewed academic journal of the American Association for the Advancement of Science (AAAS) and one of the world's top academic journals. It was first published in 1880, is currently circulated weekly and has a subscriber base of around 130,000. Because institutional subscriptions and online access serve a larger audience, its estimated readership is over 400,000 people. ''Science'' is based in Washington, D.C., United States, with a second office in Cambridge, UK. Contents The major focus of the journal is publishing important original scientific research and research reviews, but ''Science'' also publishes science-related news, opinions on science policy and other matters of interest to scientists and others who are concerned with the wide implications of science and technology. Unlike most scientific journals, which focus on a specific field, ''Science'' and its rival ''Nature'' cover the full rang ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Witold Hurewicz
Witold Hurewicz (June 29, 1904 – September 6, 1956) was a Polish mathematician. Early life and education Witold Hurewicz was born in Łódź, at the time one of the main Polish industrial hubs with economy focused on the textile industry. His father, Mieczysław Hurewicz, was an industrialist born in Wilno, which until 1939 was mainly populated by Poles and Jews. His mother was Katarzyna Finkelsztain who hailed from Biała Cerkiew, a town that belonged to the Kingdom of Poland until the Second Partition of Poland (1793) when it was taken by Russia. Hurewicz attended school in a German-controlled Poland but with World War I beginning before he had begun secondary school, major changes occurred in Poland. In August 1915 the Russian forces that had held Poland for many years withdrew. Germany and Austria-Hungary took control of most of the country and the University of Warsaw was refounded and it began operating as a Polish university. Rapidly, a strong school of mathematics gr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wallman Compactification
In mathematics, the Wallman compactification, generally called Wallman–Shanin compactification is a compactification of T1 topological spaces that was constructed by . Definition The points of the Wallman compactification ω''X'' of a space ''X'' are the maximal proper filters in the poset of closed subsets of ''X''. Explicitly, a point of ω''X'' is a family \mathcal F of closed nonempty subsets of ''X'' such that \mathcal F is closed under finite intersections, and is maximal among those families that have these properties. For every closed subset ''F'' of ''X'', the class Φ''F'' of points of ω''X'' containing ''F'' is closed in ω''X''. The topology of ω''X'' is generated by these closed classes. Special cases For normal spaces, the Wallman compactification is essentially the same as the Stone–Čech compactification. See also * Lattice (order) * Pointless topology In mathematics, pointless topology, also called point-free topology (or pointfree topology) and locale th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Disjunction Property Of Wallman
In mathematics, especially in order theory, a partially ordered set with a unique minimal element 0 has the disjunction property of Wallman when for every pair (''a'', ''b'') of elements of the poset, either ''b'' ≤ ''a'' or there exists an element ''c'' ≤ ''b'' such that ''c'' ≠ 0 and ''c'' has no nontrivial common predecessor with ''a''. That is, in the latter case, the only ''x'' with ''x'' ≤ ''a'' and ''x'' ≤ ''c'' is ''x'' = 0. A version of this property for lattices was introduced by , in a paper showing that the homology theory of a topological space could be defined in terms of its distributive lattice of closed sets. He observed that the inclusion order on the closed sets of a T1 space In topology and related branches of mathematics, a T1 space is a topological space in which, for every pair of distinct points, each has a neighborhood not containing the other point. An R0 space is one in which this holds for every pair of top ... has the disjunction property. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
