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Null Sign
The null sign (∅) is a symbol often used in mathematics for denoting the empty set. 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 or 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 a part of the Greek alphabet. The minuscul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Empty String
In formal language theory, the empty string, or empty word, is the unique String (computer science), string of length zero. Formal theory Formally, a string is a finite, ordered sequence of character (symbol), characters such as letters, digits or spaces. The empty string is the special case where the sequence has length zero, so there are no symbols in the string. There is only one empty string, because two strings are only different if they have different lengths or a different sequence of symbols. In formal treatments, the empty string is denoted with ε or sometimes Λ or λ. The empty string should not be confused with the empty language ∅, which is a formal language (i.e. a set of strings) that contains no strings, not even the empty string. The empty string has several properties: * , ε, = 0. Its string (computer science)#Formal theory, string length is zero. * ε ⋅ s = s ⋅ ε = s. The empty string is the identity element of the concatenation operation. The set of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Greek Alphabet
The Greek alphabet has been used to write the Greek language since the late 9th or early 8th century BC. It was derived from the earlier Phoenician alphabet, and is the earliest known alphabetic script to systematically write vowels as well as consonants. In Archaic Greece, Archaic and early Classical Greece, Classical times, the Greek alphabet existed in Archaic Greek alphabets, many local variants, but, by the end of the 4th century BC, the Ionia, Ionic-based Euclidean alphabet, with 24 letters, ordered from alpha to omega, had become standard throughout the Greek-speaking world and is the version that is still used for Greek writing today. The letter case, uppercase and lowercase forms of the 24 letters are: : , , , , , , , , , , , , , , , , , , , , , , , The Greek alphabet is the ancestor of several scripts, such as the Latin script, Latin, Gothic alphabet, Gothic, Coptic script, Coptic, and Cyrillic scripts. Throughout antiquity, Greek had only a single uppercas ... [...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 with three additional letters: , and . It is identical to the Norwegian alphabet. The orthography is characterized by a low degree of correspondence between writing and pronunciation. 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 ... [...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 one of the most influential mathematicians of the twentieth century. His influence is due both to his original contributions to a remarkably broad spectrum of mathematical theories, and to the mark he left on mathematical practice and style, through some of his own works as well as through the Bourbaki group, of which he was one of the principal founders. 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 Mu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bourbaki Group
Bourbaki(s) may refer to : Persons and science * Charles-Denis Bourbaki (1816–1897), French general, son of Constantin Denis Bourbaki * Colonel Constantin Denis Bourbaki (1787–1827), officer in the Greek War of Independence and serving in the French military * Nicolas Bourbaki, the collective pseudonym of a group of French mathematicians ** Séminaire Nicolas Bourbaki and its follow-ups *** Séminaire Nicolas Bourbaki (1950–1959) *** Séminaire Nicolas Bourbaki (1960–1969) ** Bourbaki–Witt theorem In mathematics, the Bourbaki–Witt theorem in order theory, named after Nicolas Bourbaki and Ernst Witt, is a basic fixed-point theorem for partially ordered sets. It states that if ''X'' is a non-empty chain complete poset, and f : X \to X such ... ** Bourbaki–Alaoglu theorem ** Jacobson–Bourbaki theorem * Nikolaos Bourbakis, computer scientist Other * A place in Algeria, now known as Khemisti, near Aïn-Tourcia and the site of ancient city and former ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Null Set
In mathematical analysis, a null set is a Lebesgue measurable set of real numbers 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. Examples Every finite or countably infinite subset of the real numbers is a null set. For example, the set of natural numbers , the set of rational numbers and the set of algebraic numbers are all countably infinite and therefore are null sets when considered as subsets of the real numbers. The Cantor set is an example of an uncountable ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Early Cyrillic Alphabet
The Early Cyrillic alphabet, also called classical Cyrillic or paleo-Cyrillic, is an alphabetic writing system that was developed in Medieval Bulgaria in the Preslav Literary School during the late 9th century. It is used to write the Church Slavonic language, and was historically used for its ancestor, Old Church Slavonic. It was also used for other languages, but between the 18th and 20th centuries was mostly replaced by the modern Cyrillic script, which is used for some Slavic languages (such as Russian language, Russian), and for East European and Asian languages that have experienced a great amount of Russian cultural influence. History The earliest form of manuscript Cyrillic, known as ''Ustav (script), ustav'', was based on Uncial script, Greek uncial script, augmented by typographic ligature, ligatures and by letters from the Glagolitic alphabet for phonemes not found in Greek. The Glagolitic script was created by the Byzantine monk Saints Cyril and Methodius, Sa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fita
Fita (Ѳ ѳ; italics: ''Ѳ ѳ'') is a letter of the Early Cyrillic alphabet. The shape and the name of the letter are derived from the Θ, Greek letter theta (Θ θ). In the ISO 9 system, Ѳ is romanized using F grave accent (F̀ f̀). In the Cyrillic numerals, Cyrillic numeral system, Fita has a numerical 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 Te (Cyrillic), Т: . Sometimes the line is drawn as low as the baseline, which makes the letter difficult to distinguish from De (Cyrillic), 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 "Theodor ... [...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 . History The Cyrillic letter Ef was derived from the Greek letter Phi (Φ φ). It merged with and eliminated the letter Fita (Ѳ) in the Russian alphabet in 1918. The name of Ef in the Early Cyrillic alphabet is ( or ), in later Church Slavonic and Russian form it became (). In the Cyrillic numeral system, Ef has a value of 500. Appearance and usage in Slavic languages 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 via Grimm's law, which remained unchanged in Slavic. ... [...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 value was specified only in 1993; until then, represented the mid central rounded vowel . 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 (the symbol for the near-close front rounded vowel). Close-mid central protruded vowel The close-mid central protruded vowel is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyrillic Script
The Cyrillic script ( ) is a writing system used for various languages across Eurasia. It is the designated national script in various Slavic languages, Slavic, Turkic languages, Turkic, Mongolic languages, Mongolic, Uralic languages, Uralic, Caucasian languages, Caucasian and Iranian languages, Iranic-speaking countries in Southeastern Europe, Eastern Europe, the Caucasus, Central Asia, North Asia, and East Asia, and used by many other minority languages. , around 250 million people in Eurasia use Cyrillic as the official script for their national languages, with Russia accounting for about half of them. With the accession of Bulgaria to the European Union on 1 January 2007, Cyrillic became the third official script of the Languages of the European Union#Writing systems, European Union, following the Latin script, Latin and Greek alphabet, Greek alphabets. The Early Cyrillic alphabet was developed during the 9th century AD at the Preslav Literary School in the First Bulga ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oe (Cyrillic)
Oe or barred O (Ө ө; italics: ) is a letter of the Cyrillic script. Shape Its form was copied from the Latin letter barred O (Ɵ ɵ) used in Jaꞑalif and other alphabets. Despite having a similar shape, it is related neither to the Greek letter theta (Θ θ/) nor to the archaic Cyrillic letter fita (Ѳ ѳ). Usage Oe is used in the alphabets of the Bashkir, Buryat, Kalmyk, Karakalpak, Kazakh, Komi-Yazva, Kyrgyz, Mongolian, Sakha, Selkup, Tatar and Tuvan languages. In Turkic languages, it commonly represents the front rounded vowels // or //. In Kazakh and Karakalpak, it may also express //. In Mongolic languages, it usually represents // or //. The letter has also been adopted in the spelling of the Komi-Yazva language, where it represents a close-mid centralized back unrounded or weakly rounded vowel //. In Kyrgyz, Mongolian and Tuvan, the Cyrillic letter can be written as a double vowel. Until a new alphabet was published in 2016, O ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
