Axel Thue
Axel Thue (; 19 February 1863 – 7 March 1922) was a Norwegian mathematician, known for his original work in diophantine approximation and combinatorics. Work Thue published his first important paper in 1909. He stated in 1914 the socalled word problem for semigroups or Thue problem, closely related to the halting problem In computability theory, the halting problem is the problem of determining, from a description of an arbitrary computer program and an input, whether the program will finish running, or continue to run forever. Alan Turing proved in 1936 that a g .... Ronald V. Book and Friedrich Otto, ''Stringrewriting Systems'', Springer, 1993, , p. 36. His only known PhD student was Thoralf Skolem. The esoteric programming language Thue is named after him. Publications * * See also * * * * * * References External links * Axel Thue private archiveexists at NTNU University LibrarDorabiblioteket 1863 births 1922 deaths 20thcentury Norwegian mathematici ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] 

Tønsberg
Tønsberg , historically Tunsberg, is a city and municipality in Vestfold og Telemark county, eastern Norway, located around southsouthwest of Oslo on the western coast of the Oslofjord near its mouth onto the Skagerrak. The administrative centre of the municipality is the city of Tønsberg. The city is the most populous metropolis in the district of Vestfold with a population of 52,419 in 2019. The municipality has a population of 56,293 and covers an area of in 2020. Tønsberg also serves as the seat for the County Governor of Vestfold og Telemark. Tønsberg is generally regarded as the oldest city in Norway, founded by Vikings in the 9th century. Tønsberg was established as a municipality on 1 January 1838 (see formannskapsdistrikt). The rural municipality of Sem was merged into the municipality of Tønsberg on 1 January 1988. The neighboring municipality of Re was merged into Tønsberg on 1 January 2020. It is home to Tønsberg Fortress on Castle Mountain, which in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] 

Combinatorics
Combinatorics is an area of mathematics primarily concerned with counting, both as a means and an end in obtaining results, and certain properties of finite structures. It is closely related to many other areas of mathematics and has many applications ranging from logic to statistical physics and from evolutionary biology to computer science. Combinatorics is well known for the breadth of the problems it tackles. Combinatorial problems arise in many areas of pure mathematics, notably in algebra, probability theory, topology, and geometry, as well as in its many application areas. Many combinatorial questions have historically been considered in isolation, giving an ''ad hoc'' solution to a problem arising in some mathematical context. In the later twentieth century, however, powerful and general theoretical methods were developed, making combinatorics into an independent branch of mathematics in its own right. One of the oldest and most accessible parts of combinatorics is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] 

1922 Deaths
Nineteen or 19 may refer to: * 19 (number), the natural number following 18 and preceding 20 * one of the years 19 BC, AD 19, 1919, 2019 Films * ''19'' (film), a 2001 Japanese film * ''Nineteen'' (film), a 1987 science fiction film Music * 19 (band), a Japanese pop music duo Albums * ''19'' (Adele album), 2008 * ''19'', a 2003 album by Alsou * ''19'', a 2006 album by Evan Yo * ''19'', a 2018 album by MHD * ''19'', one half of the double album ''63/19'' by Kool A.D. * '' Number Nineteen'', a 1971 album by American jazz pianist Mal Waldron * ''XIX'' (EP), a 2019 EP by 1the9 Songs * "19" (song), a 1985 song by British musician Paul Hardcastle. * "Nineteen", a song by Bad4Good from the 1992 album '' Refugee'' * "Nineteen", a song by Karma to Burn from the 2001 album ''Almost Heathen''. * "Nineteen" (song), a 2007 song by American singer Billy Ray Cyrus. * "Nineteen", a song by Tegan and Sara from the 2007 album '' The Con''. * "XIX" (song), a 2014 song by S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] 

1863 Births
Events January–March * January 1 – Abraham Lincoln signs the Emancipation Proclamation during the third year of the American Civil War, making the abolition of slavery in the Confederate states an official war goal. It proclaims the freedom of 3.1 million of the nation's four million slaves and immediately frees 50,000 of them, with the rest freed as Union armies advance. * January 2 – Lucius Tar Painting Master Company (''Teerfarbenfabrik Meirter Lucius''), predecessor of Hoechst, as a worldwide chemical manufacturing brand, founded in a suburb of Frankfurt am Main, Germany. * January 4 – The New Apostolic Church, a Christian and chiliastic church, is established in Hamburg, Germany. * January 7 – In the Swiss canton of Ticino, the village of Bedretto is partly destroyed and 29 killed, by an avalanche. * January 8 ** The Yorkshire County Cricket Club is founded at the Adelphi Hotel, in Sheffield, England. ** American Civil War &ndash ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] 

Journal Für Die Reine Und Angewandte Mathematik
''Crelle's Journal'', or just ''Crelle'', is the common name for a mathematics journal, the ''Journal für die reine und angewandte Mathematik'' (in English: ''Journal for Pure and Applied Mathematics''). History The journal was founded by August Leopold Crelle (Berlin) in 1826 and edited by him until his death in 1855. It was one of the first major mathematical journals that was not a proceedings of an academy. It has published many notable papers, including works of Niels Henrik Abel, Georg Cantor, Gotthold Eisenstein, Carl Friedrich Gauss and Otto Hesse. It was edited by Carl Wilhelm Borchardt from 1856 to 1880, during which time it was known as ''Borchardt's Journal''. The current editorinchief is Rainer Weissauer ( RuprechtKarlsUniversität Heidelberg) Past editors * 1826–1856 August Leopold Crelle * 1856–1880 Carl Wilhelm Borchardt * 1881–1888 Leopold Kronecker, Karl Weierstrass * 1889–1892 Leopold Kronecker * 1892–1902 Lazarus Fuchs * 1903–1928 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] 

Thue (programming Language)
Thue ( ) is an esoteric programming language invented by John Colagioia in early 2000. It is a metalanguage that can be used to define or recognize Type0 languages from the Chomsky hierarchy. Because it is able to define languages of such complexity, it is also Turingcomplete itself. Thue is based on a nondeterministic string rewriting system called semiThue grammar, which itself is named after the Norwegian mathematician Axel Thue. The author describes it as follows: "Thue represents one of the simplest possible ways to construe constraintbased programming. It is to the constraintbased paradigm what languages like OISC are to the imperative paradigm; in other words, it's a tar pit." Production rules A Thue program starts with a rulebase, which is a series of substitution rules, each of this form: ''lhs'' ::= ''rhs'' The rulebase terminates with a lone production symbol on a line: ::= The initial state is a series of symbols which follow the rulebase. Thue consume ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] 

Ronald V
Ronald is a masculine given name derived from the Old Norse ''Rögnvaldr'',#H2, Hanks; Hardcastle; Hodges (2006) p. 234; #H1, Hanks; Hodges (2003) § Ronald. or possibly from Old English ''Regenweald''. In some cases ''Ronald'' is an Anglicised form of the Gaelic ''Raghnall'', a name likewise derived from ''Rögnvaldr''. The latter name is composed of the Old Norse elements ''regin'' ("advice", "decision") and ''valdr'' ("ruler"). ''Ronald'' was originally used in England and Scotland, where Scandinavian influences were once substantial, although now the name is common throughout the Englishspeaking world. A short form of ''Ronald'' is ''Ron''. Pet forms of ''Ronald'' include ''Roni'' and ''Ronnie (given name), Ronnie''. ''Ronalda'' and ''Rhonda'' are feminine forms of ''Ronald''. ''Rhona (other), Rhona'', a modern name apparently only dating back to the late nineteenth century, may have originated as a feminine form of ''Ronald''.#H2, Hanks; Hardcastle; Hodges (2006) pp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] 

Halting Problem
In computability theory, the halting problem is the problem of determining, from a description of an arbitrary computer program and an input, whether the program will finish running, or continue to run forever. Alan Turing proved in 1936 that a general algorithm to solve the halting problem for all possible program–input pairs cannot exist. For any program that might determine whether programs halt, a "pathological" program , called with some input, can pass its own source and its input to ''f'' and then specifically do the opposite of what ''f'' predicts ''g'' will do. No ''f'' can exist that handles this case. A key part of the proof is a mathematical definition of a computer and program, which is known as a Turing machine; the halting problem is '' undecidable'' over Turing machines. It is one of the first cases of decision problems proven to be unsolvable. This proof is significant to practical computing efforts, defining a class of applications which no programming invent ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] 

SemiThue System
In theoretical computer science and mathematical logic a string rewriting system (SRS), historically called a semi Thue system, is a rewriting system over strings from a (usually finite) alphabet. Given a binary relation R between fixed strings over the alphabet, called rewrite rules, denoted by s\rightarrow t, an SRS extends the rewriting relation to all strings in which the left and righthand side of the rules appear as substrings, that is usv\rightarrow utv, where s, t, u, and v are strings. The notion of a semiThue system essentially coincides with the presentation of a monoid. Thus they constitute a natural framework for solving the word problem for monoids and groups. An SRS can be defined directly as an abstract rewriting system. It can also be seen as a restricted kind of a term rewriting system. As a formalism, string rewriting systems are Turing complete. The semiThue name comes from the Norwegian mathematician Axel Thue, who introduced systematic treatment of str ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] 

Diophantine Approximation
In number theory, the study of Diophantine approximation deals with the approximation of real numbers by rational numbers. It is named after Diophantus of Alexandria. The first problem was to know how well a real number can be approximated by rational numbers. For this problem, a rational number ''a''/''b'' is a "good" approximation of a real number ''α'' if the absolute value of the difference between ''a''/''b'' and ''α'' may not decrease if ''a''/''b'' is replaced by another rational number with a smaller denominator. This problem was solved during the 18th century by means of continued fractions. Knowing the "best" approximations of a given number, the main problem of the field is to find sharp upper and lower bounds of the above difference, expressed as a function of the denominator. It appears that these bounds depend on the nature of the real numbers to be approximated: the lower bound for the approximation of a rational number by another rational number is larger tha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] 

Norway
Norway, officially the Kingdom of Norway, is a Nordic country in Northern Europe, the mainland territory of which comprises the western and northernmost portion of the Scandinavian Peninsula. The remote Arctic island of Jan Mayen and the archipelago of Svalbard also form part of Norway. Bouvet Island, located in the Subantarctic, is a dependency of Norway; it also lays claims to the Antarctic territories of Peter I Island and Queen Maud Land. The capital and largest city in Norway is Oslo. Norway has a total area of and had a population of 5,425,270 in January 2022. The country shares a long eastern border with Sweden at a length of . It is bordered by Finland and Russia to the northeast and the Skagerrak strait to the south, on the other side of which are Denmark and the United Kingdom. Norway has an extensive coastline, facing the North Atlantic Ocean and the Barents Sea. The maritime influence dominates Norway's climate, with mild lowland temperatures on the sea co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] 