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Viggo Brun
Viggo Brun (13 October 1885 – 15 August 1978) was a Norwegian professor, mathematician and number theorist. Contributions In 1915, he introduced a new method, based on Legendre's version of the sieve of Eratosthenes, now known as the ''Brun sieve'', which addresses additive problems such as Goldbach's conjecture and the twin prime conjecture. He used it to prove that there exist infinitely many integers ''n'' such that ''n'' and ''n''+2 have at most nine prime factors, and that all large even integers are the sum of two numbers with at most nine prime factors. He also showed that the sum of the reciprocals of twin primes converges to a finite value, now called Brun's constant: by contrast, the sum of the reciprocals of all primes is divergent. He developed a multi-dimensional continued fraction algorithm in 1919–1920 and applied this to problems in musical theory. He also served as praeses of the Royal Norwegian Society of Sciences and Letters in 1946. Biography B ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Norwegian Mathematicians
A mathematician is a scholar in the fields of mathematics. They solve and research mathematical problems which can be applied in real life or completely abstract (pure). This article covers notable mathematicans from Norway. A pioneer of modern mathematics, Niels Henrik Abel contributed greatly towards various fields of mathematics during his short life. He died in 1829, aged 26, from tuberculosis. German mathematician Felix Klein spoke of his reluctance "to part from this ideal type of researcher". In 2001, the Abel Prize was established in his honour. Other notable mathematicians include (in alphabetical order) Carl Anton Bjerknes, Vilhelm Bjerknes, Bernt Michael Holmboe, who is known for being Abel's teacher and tutor, Sophus Lie, Idun Reiten, Atle Selberg, Thoralf Skolem and Carl Størmer. Alphabetical order ''"Aa" appears under "å" as they are considered different representations of the same letter.'' See also *Archiv for Mathematik og Naturvidenskab *Bjerknes (lunar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
University Of Oslo
The University of Oslo ( no, Universitetet i Oslo; la, Universitas Osloensis) is a public research university located in Oslo, Norway. It is the highest ranked and oldest university in Norway. It is consistently ranked among the top universities in the world and as one of the leading universities of Northern Europe; the Academic Ranking of World Universities ranked it the 58th best university in the world and the third best in the Nordic countries. In 2016, the Times Higher Education World University Rankings listed the university at 63rd, making it the highest ranked Norwegian university. Originally named the Royal Frederick University, the university was established in 1811 as the de facto Norwegian continuation of Denmark-Norway's common university, the University of Copenhagen, with which it shares many traditions. It was named for King Frederick VI of Denmark and Norway, and received its current name in 1939. The university was commonly nicknamed "The Royal Frederic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
People From Lier, Norway
A person ( : people) is a being that has certain capacities or attributes such as reason, morality, consciousness or self-consciousness, and being a part of a culturally established form of social relations such as kinship, ownership of property, or legal responsibility. The defining features of personhood and, consequently, what makes a person count as a person, differ widely among cultures and contexts. In addition to the question of personhood, of what makes a being count as a person to begin with, there are further questions about personal identity and self: both about what makes any particular person that particular person instead of another, and about what makes a person at one time the same person as they were or will be at another time despite any intervening changes. The plural form "people" is often used to refer to an entire nation or ethnic group (as in "a people"), and this was the original meaning of the word; it subsequently acquired its use as a plural form of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1978 Deaths
Events January * January 1 – Air India Flight 855, a Boeing 747 passenger jet, crashes off the coast of Bombay, killing 213. * January 5 – Bülent Ecevit, of CHP, forms the new government of Turkey (42nd government). * January 6 – The Holy Crown of Hungary (also known as Stephen of Hungary Crown) is returned to Hungary from the United States, where it was held since World War II. * January 10 – Pedro Joaquín Chamorro Cardenal, a critic of the Nicaraguan government, is assassinated; riots erupt against Somoza's government. * January 18 – The European Court of Human Rights finds the British government guilty of mistreating prisoners in Northern Ireland, but not guilty of torture. * January 22 – Ethiopia declares the ambassador of West Germany '' persona non grata''. * January 24 ** Soviet satellite Kosmos 954 burns up in Earth's atmosphere, scattering debris over Canada's Northwest Territories. ** Rose Dugdale and Eddie Gallagher become the first conv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1885 Births
Events January–March * January 3– 4 – Sino-French War – Battle of Núi Bop: French troops under General Oscar de Négrier defeat a numerically superior Qing Chinese force, in northern Vietnam. * January 4 – The first successful appendectomy is performed by Dr. William W. Grant, on Mary Gartside. * January 17 – Mahdist War in Sudan – Battle of Abu Klea: British troops defeat Mahdist forces. * January 20 – American inventor LaMarcus Adna Thompson patents a roller coaster. * January 24 – Irish rebels damage Westminster Hall and the Tower of London with dynamite. * January 26 – Mahdist War in Sudan: Troops loyal to Mahdi Muhammad Ahmad conquer Khartoum; British commander Charles George Gordon is killed. * February 5 – King Leopold II of Belgium establishes the Congo Free State, as a personal possession. * February 9 – The first Japanese arrive in Hawaii. * February 16 – Charles D ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ragnvald Iversen
Ragnvald Iversen (January 18, 1882 – August 21, 1960) was a Norwegian educator and professor of North Germanic linguistics.''Store norske leksikon'': Ragnvald Iversen. Iversen was born in . After passing his in 1899 at the Kongsbakken Upper Secondary School, he moved to Oslo, where he worked as a teacher (among other places, at Brandbu Middle School from 1907 to 1909) while studying. He received his |
Heini Halberstam
Heini Halberstam (11 September 1926 oreen Halberstam, wife/ref> – 25 January 2014) was a Czech-born British mathematician, working in the field of analytic number theory. He is remembered in part for the Elliott–Halberstam conjecture from 1968. Life and career Halberstam was born in Most, Czechoslovakia and died in Champaign, Illinois, US. His father died when he was very young. After Adolf Hitler's annexation of the Sudetenland, he and his mother moved to Prague. At the age of twelve, as the Nazi occupation progressed, he was one of the 669 children saved by Sir Nicholas Winton, who organized the Kindertransport, a train that allowed those children to leave Nazi-occupied territory. He was sent to England, where he lived during World War II. He obtained his PhD in 1952, from University College, London, under supervision of Theodor Estermann. From 1962 until 1964, Halberstam was Erasmus Smith's Professor of Mathematics at Trinity College Dublin; From 1964 until 19 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sieve Theory
Sieve theory is a set of general techniques in number theory, designed to count, or more realistically to estimate the size of, sifted sets of integers. The prototypical example of a sifted set is the set of prime numbers up to some prescribed limit ''X''. Correspondingly, the prototypical example of a sieve is the sieve of Eratosthenes, or the more general Legendre sieve. The direct attack on prime numbers using these methods soon reaches apparently insuperable obstacles, in the way of the accumulation of error terms. In one of the major strands of number theory in the twentieth century, ways were found of avoiding some of the difficulties of a frontal attack with a naive idea of what sieving should be. One successful approach is to approximate a specific sifted set of numbers (e.g. the set of prime numbers) by another, simpler set (e.g. the set of almost prime numbers), which is typically somewhat larger than the original set, and easier to analyze. More sophisticated sieves als ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brun's Theorem
In number theory, Brun's theorem states that the sum of the Multiplicative inverse, reciprocals of the twin primes (pairs of prime numbers which differ by 2) Convergent series, converges to a finite value known as Brun's constant, usually denoted by ''B''2 . Brun's theorem was proved by Viggo Brun in 1919, and it has historical importance in the introduction of Sieve theory, sieve methods. Asymptotic bounds on twin primes The convergence of the sum of reciprocals of twin primes follows from bounds on the Schnirelmann density, density of the sequence of twin primes. Let \pi_2(x) denote the number of prime number, primes ''p'' ≤ ''x'' for which ''p'' + 2 is also prime (i.e. \pi_2(x) is the number of twin primes with the smaller at most ''x''). Then, for ''x'' ≥ 3, we have : \pi_2(x) =O\left(\frac \right). That is, twin primes are less frequent than prime numbers by nearly a logarithmic factor. It follows from this bound that the sum of the reciprocals of the twin primes conve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Akershus
Akershus () is a traditional region and current electoral district in Norway, with Oslo as its main city and traditional capital. It is named after the Akershus Fortress in Oslo. From the middle ages to 1919, Akershus was a fief and main county that included most of Eastern Norway, and from the 17th century until 2020, Akershus also had a more narrow meaning as a (sub) county that included most of the Greater Oslo Region. After 2020 the former county of Akershus was merged into Viken along with the former counties of Østfold and Buskerud. In 2022 the Storting voted to dissolve Viken and reestablish Akershus county. Originally Akershus was one of four main fiefs in Norway and included almost all of Eastern Norway. The original Akershus became a main county (''Stiftamt'' or ''Stift'') in 1662 and was sometimes also known as ''Christiania Stift''. It included several subcounties (''Amt'' or ''Underamt''); in 1682 its most central areas, consisting of modern Oslo and Akershus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drøbak
Drøbak is a town and the centre of the municipality of Frogn, in Viken county, Norway. The city is located along the Oslofjord, and has 13,409 inhabitants. History Drøbak and Frogn was established as a parish on its own through a royal decree on 8 September 1823. It had been a part of Ås parish. Drøbak was established as a municipality on 1 January 1838 (see formannskapsdistrikt). It was merged with Frogn on 1 January 1962. Traditionally, Drøbak was the winter harbour of Norway's capital, Oslo, since in severe winters the fjord will freeze from outside Drøbak all the way up to Oslo. It had city status between 1842 and 1962, upon which point the municipality was merged into the rural municipality Frogn and lost its city status. The city status was regained by the municipality council on 13 February 2006. It was also decided that adjacent villages such as Heer would be included within the city. A notable event in Drøbak's history is the World War II sinking of the Ger ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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