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Null Sign
The null sign (∅) is often used in mathematics for denoting the empty set (however, the variant \emptyset seems more commonly used). The same letter in linguistics represents zero, the lack of an element. It is commonly used in phonology, morphology, and syntax. Encodings The symbol ∅ is available at Unicode point U+2205. It can be coded in HTML as and as . It can be coded in LaTeX as . Similar letters Similar letters and symbols include the following: * Diameter sign in geometry: * Scandinavian letter Ø: majuscule and minuscule are a part of the alphabet of Scandinavian languages. The minuscule letter is also used in the International Phonetic Alphabet (IPA) to represent close-mid front rounded vowel. * Greek letter Φ: majuscule and minuscule are a part of the Greek alphabet. It sometimes take the form of and is used as a sign in different fields of studies. The is used in the IPA for voiceless bilabial fricative. * Greek letter Θ: majuscule and minuscule are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mathematics
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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Theta
Theta (, ; uppercase: Θ or ; lowercase: θ or ; grc, ''thē̂ta'' ; Modern: ''thī́ta'' ) is the eighth letter of the Greek alphabet, derived from the Phoenician letter Teth . In the system of Greek numerals, it has a value of 9. Greek In Ancient Greek, θ represented the aspirated voiceless dental plosive , but in Modern Greek it represents the voiceless dental fricative . Forms In its archaic form, θ was written as a cross within a circle (as in the Etruscan or ), and later, as a line or point in circle ( or ). The cursive form was retained by Unicode as , separate from . (There is also ). For the purpose of writing Greek text, the two can be font variants of a single character, but are also used as distinct symbols in technical and mathematical contexts. Extensive lists of examples follow below at Mathematics and Science. is also common in biblical and theological usage e.g. instead of πρόθεσις (means placing in public or laying out a corpse). ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phi (letter)
Phi (; uppercase Φ, lowercase φ or ϕ; grc, ϕεῖ ''pheî'' ; Modern Greek: ''fi'' ) is the 21st letter of the Greek alphabet. In Archaic and Classical Greek (c. 9th century BC to 4th century BC), it represented an aspirated voiceless bilabial plosive (), which was the origin of its usual romanization as . During the later part of Classical Antiquity, in Koine Greek (c. 4th century BC to 4th century AD), its pronunciation shifted to that of a voiceless bilabial fricative (), and by the Byzantine Greek period (c. 4th century AD to 15th century AD) it developed its modern pronunciation as a voiceless labiodental fricative (). The romanization of the Modern Greek phoneme is therefore usually . It may be that phi originated as the letter qoppa (Ϙ, ϙ), and initially represented the sound before shifting to Classical Greek . In traditional Greek numerals, phi has a value of 500 () or 500,000 (). The Cyrillic letter Ef (Ф, ф) descends from phi. As with other Gr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Norwegian Orthography
Norwegian orthography is the method of writing the Norwegian language, of which there are two written standards: Bokmål and Nynorsk. While Bokmål has for the most part derived its forms from the written Danish language and Danish-Norwegian speech, Nynorsk gets its word forms from Aasen's reconstructed "base dialect", which is intended to represent the distinctive dialectal forms. Both standards use a 29-letter variant of the Latin alphabet and the same orthographic principles. Alphabet The Norwegian alphabet is based upon the Latin alphabet and is identical to the Danish alphabet. Since 1917 it has consisted of the following 29 letters. The letters c, q, w, x and z are not used in the spelling of indigenous Norwegian words. They are rarely used; loanwords routinely have their orthography adapted to the native sound system. Diacritics Norwegian (especially the Nynorsk variant) also uses several letters with diacritic signs: é, è, ê, ó, ò, ô, and ù. The diacritic s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Danish Orthography
Danish orthography is the system and norms used for writing the Danish language, including spelling and punctuation. Officially, the norms are set by the Danish language council through the publication of Retskrivningsordbogen. Danish currently uses a 29-letter Latin-script alphabet, identical to the Norwegian alphabet, with an additional three letters: '' Æ'', '' Ø'' and '' Å''. History There were spelling reforms in 1872, 1889 (with some changes in 1892), and 1948. These spelling reforms were based in the decisions of the Nordic spelling conference of 1869, whose goal was to abolish spellings that are justified by neither phonetics nor etymology and to bring Danish and Swedish orthographies closer. The reform of 1872 replaced the letter by in some words (> , > , > ; however, for words with the change was reverted in 1889), abolished the distinction of the homophonous words ''Thing'' and ''Ting'' (however, the distinction between and was retained), replaced the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
André Weil
André Weil (; ; 6 May 1906 – 6 August 1998) was a French mathematician, known for his foundational work in number theory and algebraic geometry. He was a founding member and the ''de facto'' early leader of the mathematical Bourbaki group. The philosopher Simone Weil was his sister. The writer Sylvie Weil is his daughter. Life André Weil was born in Paris to agnostic Alsatian Jewish parents who fled the annexation of Alsace-Lorraine by the German Empire after the Franco-Prussian War in 1870–71. Simone Weil, who would later become a famous philosopher, was Weil's younger sister and only sibling. He studied in Paris, Rome and Göttingen and received his doctorate in 1928. While in Germany, Weil befriended Carl Ludwig Siegel. Starting in 1930, he spent two academic years at Aligarh Muslim University in India. Aside from mathematics, Weil held lifelong interests in classical Greek and Latin literature, in Hinduism and Sanskrit literature: he had taught himself Sanskrit in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bourbaki Group
Nicolas Bourbaki () is the collective pseudonym of a group of mathematicians, predominantly French alumni of the École normale supérieure - PSL (ENS). Founded in 1934–1935, the Bourbaki group originally intended to prepare a new textbook in analysis. Over time the project became much more ambitious, growing into a large series of textbooks published under the Bourbaki name, meant to treat modern pure mathematics. The series is known collectively as the ''Éléments de mathématique'' (''Elements of Mathematics''), the group's central work. Topics treated in the series include set theory, abstract algebra, topology, analysis, Lie groups and Lie algebras. Bourbaki was founded in response to the effects of the First World War which caused the death of a generation of French mathematicians; as a result, young university instructors were forced to use dated texts. While teaching at the University of Strasbourg, Henri Cartan complained to his colleague André Weil of the inad ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Null Set
In mathematical analysis, a null set N \subset \mathbb is a measurable set that has measure zero. This can be characterized as a set that can be covered by a countable union of intervals of arbitrarily small total length. The notion of null set should not be confused with the empty set as defined in set theory. Although the empty set has Lebesgue measure zero, there are also non-empty sets which are null. For example, any non-empty countable set of real numbers has Lebesgue measure zero and therefore is null. More generally, on a given measure space M = (X, \Sigma, \mu) a null set is a set S\in\Sigma such that \mu(S) = 0. Example Every finite or countably infinite subset of the real numbers is a null set. For example, the set of natural numbers and the set of rational numbers are both countably infinite and therefore are null sets when considered as subsets of the real numbers. The Cantor set is an example of an uncountable null set. Definition Suppose A is a subs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Early Cyrillic Alphabet
The Early Cyrillic alphabet, also called classical Cyrillic or paleo-Cyrillic, is a writing system that was developed in the First Bulgarian Empire during the late 9th century on the basis of the Greek alphabet for the Slavic people living near the Byzantine Empire in South East and Central Europe. It was used by Slavic peoples in South East, Central and Eastern Europe. It was developed in the Preslav Literary School in the capital city of the First Bulgarian Empire in order to write the Old Church Slavonic language. The modern Cyrillic script is still used primarily for some Slavic languages (such as Bulgarian, Macedonian, Serbian, Russian and Ukrainian), Kazakhstanand for East European and Asian languages that have experienced a great amount of Russian cultural influence. Among some of the traditionally culturally influential countries using Cyrillic script are Bulgaria, Russia, Serbia and Ukraine. Set А Б В Г Д Є Ж З И І К Л М Н О П Р С Т Ꙋ Ф ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fita
Fita (Ѳ ѳ; italics: ) is a letter of the Early Cyrillic alphabet. The shape and the name of the letter are derived from the Greek letter theta (Θ θ). In the ISO 9 system, Ѳ is romanized using F grave accent (F̀ f̀). In the Cyrillic numeral system, Fita has a value of 9. Shape In traditional (Church Slavonic) typefaces, the central line is typically about twice the width of the letter's body and has serifs similar to those on the letter Т: . Sometimes the line is drawn as low as the baseline, which makes the letter difficult to distinguish from Д. Usage Old Russian and Church Slavonic The traditional Russian name of the letter is ''fitá'' (or, in pre-1918 spelling, ѳита́). Fita was mainly used to write proper names and loanwords derived from or via Greek. Russians pronounced these names with the sound instead of (like the pronunciation of in "thin"), for example "Theodore" was pronounced as "Feodor" (now "Fyodor"). Early texts in Russian ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ef (Cyrillic)
Ef or Fe (Ф ф; italics: ) is a Cyrillic letter, commonly representing the voiceless labiodental fricative , like the pronunciation of in "fill, flee, or fall". The Cyrillic letter Ef is romanized as . In some languages it is known as Fe. History The Cyrillic letter Ef was derived from the Greek letter Phi (Φ φ). It merged with an eliminated letter Fita (Ѳ) in the Russian alphabet in 1918. The name of Ef in the Early Cyrillic alphabet is (''fr̥tŭ'' or ''frĭtŭ''), in later Church Slavonic and Russian form it became ''фертъ'' (''fert''). In the Cyrillic numeral system, Ef has a value of 500. Appearance The Slavic languages have almost no native words containing . This sound did not exist in Proto-Indo-European (PIE). It arose in Greek and Latin from PIE (which yielded Slavic ). In some instances in Latin, it represented historical th-fronting and derived from Proto-Indo-European . In the Germanic languages, the f sound arose from PIE , which remain ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Close-mid Central Rounded Vowel
The close-mid central rounded vowel, or high-mid central rounded vowel, is a type of vowel sound. The symbol in the International Phonetic Alphabet that represents this sound is , a lowercase barred letter o. The character ɵ has been used in several Latin-derived alphabets such as the one for Yañalif but then denotes a sound that is different from that of the IPA. The character is homographic with Cyrillic Ө. The Unicode code point is . This vowel occurs in Cantonese, Dutch, French, Russian and Swedish as well as in a number of English dialects as a realization of (as in ''foot''), (as in ''nurse'') or (as in ''goat''). This sound rarely contrasts with the near-close front rounded vowel and so is sometimes transcribed with the symbol . Close-mid central protruded vowel The close-mid central protruded vowel is typically transcribed in IPA simply as , and that is the convention used in this article. As there is no dedicated diacritic A diacritic (also diacriti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
