1.
Slashed zero
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The slashed zero is a representation of the number 0, with a slash through it. It thus helps to differentiate characters that would otherwise be homoglyphs and it was commonly used during the punched card era, when programs were typically written out by hand, to avoid ambiguity when the character was later typed on a card punch. Unlike in the Scandinavian vowel Ø and the empty set symbol ∅, however, the slashed zero is sometimes approximated by overlaying zero and slash characters, producing the character 0̸. In character encoding terms, it has no explicit codepoint, the slashed zero long predates computers, and is known to have been used in the twelfth and thirteenth centuries. It is used in many Baudot teleprinter applications, specifically the keytop and typepallet that combines P, additionally, the slashed zero is used in many ASCII graphic sets descended from the default typewheel on the Teletype Model 33. The slashed zero is used in a number of fields in order to avoid confusion with the letter O and it is used by computer programmers, in recording amateur radio call signs and in military radio, as logs of such contacts tend to contain both letters and numerals. The slashed zero, sometimes called zero, was used on teleprinter circuits for weather applications. The slashed zero can be used in stoichiometry to avoid confusion with the symbol for oxygen, along with the Westminster, MICR, and OCR-A fonts, the slashed zero became one of the things associated with hacker culture in the 1980s. Some cartoons depicted computer users talking in code with 1s. To generate a slashed zero on typewriters, typists would type a normal O or zero, backspace, in Microsoft Word it can be easily generated by CTRL-Forward Slash, followed by Shift-O. Slashed zeroes have been used in the Flash-based artwork of Young-Hae Chang Heavy Industries, notably in their 2003 work, the reason for their use is unknown, but has been conjectured to be related to themes of negation, erasure, and absence. Slashed zeroes can also be used on cheques in order to prevent fraud, for example, the slashed o is also used by the Grammy Award-Winning American band Twenty One Pilots, sometimes stylized as twenty øne piløts. The treatment of slashed zero as a glyph is supported by any font whose designer chose the option, successful display on any local system depends on having the font available there, either via the systems font files or via font embedding. Unicode supports explicit slashed zero, but only via a pair of combining characters and it is treated literally as a zero that is slashed, and it is coded as two characters, the commonplace zero and then the combining long solidus overlay. These combining characters overlay the preceding character, creating a composite glyph, when used in HTML, use of such combining characters is valid but not yet supported by all current web browsers, for instance, Microsoft Internet Explorer fails to render them. They may be coded as 0̸, giving 0̸, unicode 9.0 introduced another method to create a short diagonal stroked form of zero by utilizing the Variation Selector 1 in the sequence U+0030 U+FE00. It causes problems for some Scandinavian languages — Ø is used as a letter in the Danish, Faroese, and Norwegian alphabets and it also resembles the Greek letters Theta and Phi in some fonts. The symbols Ø and ∅ are used in mathematics to refer to the empty set, ⌀ is Unicodes codepoint for the diameter symbol

2.
Sid Wilson
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Sidney George Wilson also known as Ratboy or DJ Starscream, #0, is an American DJ, keyboardist and pianist, best known as the turntablist of the Grammy Award-winning band Slipknot. Wilson was the youngest member of the band until bassist Alessandro Venturella and drummer Jay Weinberg, Sid Wilson was born and raised in Des Moines, Iowa. He performs in the American band Slipknot, and also tours as DJ Starscream and he is a fan of the Transformers franchise, and has Transformer tattoos. Musically within Slipknot, Wilson contributes scratching, sound effects, horrorlike noises as well as background noises/effects, when numbers were being assigned to each band member, he insisted on being the number zero since it epitomized filth. He is also known to dive in Slipknots early years. Outside Slipknot, Wilson has made a following in Japan as a musician, under the pseudonym DJ Starscream. A remix of the track appeared on the Wagdug Futuristic Unity mini-album Nu Riot and 2008 album Hakai. As of August 2010, he is touring with his solo band SID and he is the lead vocalist of the band. Wilson went on tour with his band, his last tour date was on September 5,2010 at a music venue called Another Hole In The Wall, located in Steger. He stated, This is the best stop on the tour and it really made me feel like I got back to my roots. He also said that he will be touring with his project for a year or two. The debut album SID was released on September 13,2011 for digital download, in 2013 he was a support act for Vamps at their shows in Los Angeles and New York. During his time with Slipknot, Sids mask has been, for the most part, during the tour for Iowa, Sid wore gas masks that had been customised to resemble skulls. During the Subliminal Verses World Tour, Sid grew his hair long and began to wear masks that simply resembled skulls. In promotional photos for All Hope is Gone and the tour for the album, Sid changed his mask again and he once again cut his hair short, this time into a Fauxhawk style, and dyed it red. The eyebrows of the mask are able to be controlled by Sid, in 2013 Sid announced a new mask which he debuted over the weekend at Ozzfest Japan in Tokyo. The mask was made by Ukrainian design studio Bob Basset and this and the subsequent masks made by Basset are all made of leather and have a style reminiscent of Sids earlier gas masks. The mask also has a metal cup that can be placed over the mouth

3.
42nd Street Shuttle
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The 42nd Street Shuttle is a New York City Subway shuttle train service that operates in Manhattan. Part of a former Interborough Rapid Transit Company line, it is referred to as the Grand Central/Times Square Shuttle. It runs at all times except nights, connecting Times Square to Grand Central under 42nd Street. It is the shortest regular service in the system, running about 2,700 feet in two minutes. The 42nd Street Shuttle is part of the A Division of New York City Transit, in order to distinguish it from the other shuttles in the system, NYCT Rapid Transit Operations internally refers to it as the 0. Its route bullet is colored slate gray on route signs, station signs. The subway through which the shuttle runs was opened on October 27,1904, in 1910, the platforms at the two stations were extended. A plan called the Dual System of Rapid Transit in 1913 was worked out with the Interborough Rapid Transit and the Brooklyn Rapid Transit companies, as part of the plan, the existing IRT subway would be reconfigured into what was called the H system. From 42nd Street, new lines would be built northward in Lexington Avenue and southward in Seventh Avenue, connecting with the old subway to form East Side, the leftover segment under 42nd Street was to be used for a shuttle connecting the two main lines. 400 feet was left between the end of the old station and the new station, and therefore a new station was to be built for the shuttle, ending close to the new station on the Lexington Avenue Line. Trackways were built continuing east under 42nd Street to bring the two tracks into the new station, which was a narrow island platform between the two tracks. It was expected that two tracks would be more adequate for the shuttle. The station was not ready in time, and therefore temporary wooden flooring was laid over part of the trackways at Times Square, the shuttle was heavily used, and the crowding conditions were so bad that the shuttle was ordered closed the next day by the Public Service Commission. The new, unused trackways of the station were covered with flooring. The shuttle reopened on September 28,1918, with improved passageways, Track 2 at the Grand Central station was covered over by a wooden platform. On the walls of the stations, black bands and green bands were painted to guide passengers to the shuttle platforms. The shuttle was meant to be temporary, and by 1920, throughout the history of the shuttle there have been proposals to extend and improve the line both to the east and to the west. However, it is not feasible to extend the line in direction, as the line is at the same level as the tracks of the Broadway–Seventh Avenue Line

4.
Symbols for zero
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The modern numerical digit 0 is usually written as a circle, an ellipse, or a rounded rectangle. In most modern typefaces, the height of the 0 character is the same as the other digits, however, in typefaces with text figures, the character is often shorter. Traditionally, many print typefaces made the capital letter O more rounded than the narrower, typewriters originally made no distinction in shape between O and 0, some models did not even have a separate key for the digit 0. The distinction came into prominence on modern character displays, the digit 0 with a dot in the centre seems to have originated as an option on IBM3270 displays. Its appearance has continued with Taligents command line typeface Andalé Mono, one variation used a short vertical bar instead of the dot. This could be confused with the Greek letter Theta on a badly focused display and this form is similar to the symbol ∅, or ∅, representing the empty set, as well as to the letter Ø used in several Scandinavian languages. Some Burroughs/Unisys equipment displays a digit 0 with a reversed slash, others advocated the opposite convention, including IBM for writing Algol programs. Another convention used on early line printers left digit 0 unornamented but added a tail or hook to the capital O so that it resembled an inverted Q or cursive capital letter-O. Some fonts designed for use with computers made one of the pair more rounded. The Texas Instruments TI-99/4A computer featured a more angular capital O, sometimes the digit 0 is used either exclusively, or not at all, to avoid confusion altogether. In Braille, the numeral 0 has the same dot configuration as the letter J. Arabic numeral variations#Slashed zero Regional handwriting variation#Arabic numerals

5.
O
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O is the 15th letter and the second-to-last vowel in the modern English alphabet and the ISO basic Latin alphabet. Its graphic form has remained constant from Phoenician times until today. The name of the Phoenician letter was ʿeyn, meaning eye and its original sound value was that of a consonant, probably, the sound represented by the cognate Arabic letter ع ʿayn. The use of this Phoenician letter for a sound is due to the early Greek alphabets. The letter was adopted with this value in the Old Italic alphabets, in Greek, a variation of the form later came to distinguish this long sound from the short o. Greek omicron gave rise to the corresponding Cyrillic letter O and the early Italic letter to runic ᛟ, the letter ⟨o⟩ is the fourth most common letter in the English alphabet. Like the other English vowel letters, it has associated long, the long ⟨o⟩ as in boat is actually most often a diphthong /oʊ/. In English there is also a short ⟨o⟩ as in fox, /ɒ/, which sounds slightly different in different dialects. In most dialects of British English, it is either an open-mid back rounded vowel or a back rounded vowel, in American English. In other contexts, especially before a letter with a minim, ⟨o⟩ may represent the sound /ʌ/, in English, the letter ⟨o⟩ in isolation before a noun, usually capitalized, marks the vocative case, as in the titles to O Canada or O Captain. Or certain verses of the Bible, ⟨o⟩ is commonly associated with the open-mid back rounded vowel, mid back rounded vowel or close-mid back rounded vowel in many languages. Other languages use ⟨o⟩ for various values, usually back vowels which are at least partly open, derived letters such as ⟨ö⟩ and ⟨ø⟩ have been created for the alphabets of some languages to distinguish values that were not present in Latin and Greek, particularly rounded front vowels. In the International Phonetic Alphabet, ⟨o⟩ represents the close-mid back rounded vowel, oxygen = O O mark Media related to O at Wikimedia Commons The dictionary definition of O at Wiktionary The dictionary definition of o at Wiktionary

6.
Empty set
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In mathematics, and more specifically set theory, the empty set is the unique set having no elements, its size or cardinality is zero. Some axiomatic set theories ensure that the empty set exists by including an axiom of empty set, in other theories, many possible properties of sets are vacuously true for the empty set. Null set was once a synonym for empty set, but is now a technical term in measure theory. The empty set may also be called the void set, common notations for the empty set include, ∅, and ∅. The latter two symbols were introduced by the Bourbaki group in 1939, inspired by the letter Ø in the Norwegian, although now considered an improper use of notation, in the past,0 was occasionally used as a symbol for the empty set. The empty-set symbol ∅ is found at Unicode point U+2205, in LaTeX, it is coded as \emptyset for ∅ or \varnothing for ∅. In standard axiomatic set theory, by the principle of extensionality, hence there is but one empty set, and we speak of the empty set rather than an empty set. The mathematical symbols employed below are explained here, in this context, zero is modelled by the empty set. For any property, For every element of ∅ the property holds, There is no element of ∅ for which the property holds. Conversely, if for some property and some set V, the two statements hold, For every element of V the property holds, There is no element of V for which the property holds. By the definition of subset, the empty set is a subset of any set A. That is, every element x of ∅ belongs to A. Indeed, since there are no elements of ∅ at all, there is no element of ∅ that is not in A. Any statement that begins for every element of ∅ is not making any substantive claim and this is often paraphrased as everything is true of the elements of the empty set. When speaking of the sum of the elements of a finite set, the reason for this is that zero is the identity element for addition. Similarly, the product of the elements of the empty set should be considered to be one, a disarrangement of a set is a permutation of the set that leaves no element in the same position. The empty set is a disarrangment of itself as no element can be found that retains its original position. Since the empty set has no members, when it is considered as a subset of any ordered set, then member of that set will be an upper bound. For example, when considered as a subset of the numbers, with its usual ordering, represented by the real number line

7.
Phi
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Phi is the 21st letter of the Greek alphabet. In Ancient Greek, it represented a voiceless bilabial plosive. In modern Greek, it represents a voiceless fricative and is correspondingly romanized as f. Its origin is uncertain but it may be that phi originated as the letter qoppa, in traditional Greek numerals, phi has a value of 500 or 500 000. The Cyrillic letter Ef descends from phi, phi is also used as a symbol for the golden ratio and on other occasions in math and science. This use is separately encoded as the Unicode glyph ϕ, the modern Greek pronunciation of the letter is sometimes encountered in English when the letter is being used in this sense. The lower-case letter φ is often used to represent the following, Magnetic flux in physics The golden ratio 1 +52 ≈1.618033988749894848204586834. in mathematics, art, Eulers totient function φ in number theory, also called Eulers phi function. The cyclotomic polynomial functions Φn of algebra, in algebra, group or ring homomorphisms In probability theory, ϕ = −½e−x2/2 is the probability density function of the normal distribution. In probability theory, φX = E is the function of a random variable X. An angle, typically the second angle mentioned, after θ, especially, The argument of a complex number. The phase of a wave in signal processing, in spherical coordinates, mathematicians usually refer to phi as the polar angle. The convention in physics is to use phi as the azimuthal angle, one of the dihedral angles in the backbones of proteins in a Ramachandran plot Internal or effective angle of friction. The work function of a surface, in solid-state physics, a shorthand representation for an aromatic functional group in organic chemistry. The ratio of free energy destabilizations of protein mutants in phi value analysis, in cartography, geodesy and navigation, latitude. In aircraft flight mechanics as the symbol for bank angle, in combustion engineering, fuel–air equivalence ratio. The ratio between the fuel air ratio to the stoichiometric fuel air ratio. The Veblen function in set theory Porosity in geology and hydrology, strength reduction factor in structural engineering, used to account for statistical variabilities in materials and construction methods. The symbol for a voiceless fricative in the International Phonetic Alphabet In economics

8.
Theta
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Theta 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, in Ancient Greek, θ represented the aspirated voiceless dental plosive /t̪ʰ/, but in Modern Greek it represents the voiceless dental fricative /θ/. In its archaic form, θ was written as a cross within a circle, archaic crossed forms of theta are seen in the wheel letters of Linear A and Linear B. The cursive form ϑ was retained by Unicode as U+03D1 ϑ GREEK THETA SYMBOL, for the purpose of writing Greek text, the two can be font variants of a single character, but θ and ϑ are also used as distinct symbols in technical and mathematical contexts. In the Latin script used for the Gaulish language, theta developed into the tau gallicum, conventionally transliterated as Ð, the phonetic value of the tau gallicum is thought to have been. The early Cyrillic letter fita developed from θ and this letter existed in the Russian alphabet until the 1918 Russian orthography reform. In the International Phonetic Alphabet, represents the voiceless dental fricative and it does not represent the consonant in the, which is the voiced dental fricative. The lower-case letter θ is used as a symbol for, A plane angle in geometry, a Variable in trigonometry A special function of several complex variables. One of the Chebyshev functions in prime number theory, the score of a test taker in item response theory. Theta Type Replication, a type of bacterial DNA replication specific to circular chromosomes, threshold value of an artificial neuron. A Bayer designation letter applied to a star in a constellation, usually the star so labelled. The parameter frequently used in writing the likelihood function, the Watterson estimator for the population mutation rate in population genetics. Indicates a minimum optimum integration level determined by the intersection of GG, the GG-LL schedules are a tool used in analyzing the potential benefits of a country pegging their domestic currency to a foreign currency. The reserve ratio of banks in economic models, the ordinal collapsing function developed by Solomon Feferman The upper-case letter Θ is used as a symbol for, Quantity or temperature, by SI standard. An asymptotically tight bound in the analysis of algorithms, a certain ordinal number in set theory. Pentaquarks, exotic baryons in particle physics, a brain signal frequency ranging from 4–8 Hz. One of the known as Greeks in finance, representing time decay of options or the change in the intrinsic value of an option divided by the number of days until the option expires. A variable indicating temperature difference in heat transfer, according to Porphyry of Tyros, the Egyptians used an X within a circle as a symbol of the soul, having a value of nine, it was used as a symbol for Ennead

9.
Diameter
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In geometry, a diameter of a circle is any straight line segment that passes through the center of the circle and whose endpoints lie on the circle. It can also be defined as the longest chord of the circle, both definitions are also valid for the diameter of a sphere. In more modern usage, the length of a diameter is called the diameter. In this sense one speaks of the rather than a diameter, because all diameters of a circle or sphere have the same length. Both quantities can be calculated efficiently using rotating calipers, for a curve of constant width such as the Reuleaux triangle, the width and diameter are the same because all such pairs of parallel tangent lines have the same distance. For an ellipse, the terminology is different. A diameter of an ellipse is any chord passing through the midpoint of the ellipse, for example, conjugate diameters have the property that a tangent line to the ellipse at the endpoint of one of them is parallel to the other one. The longest diameter is called the major axis, the word diameter is derived from Greek διάμετρος, diameter of a circle, from διά, across, through and μέτρον, measure. It is often abbreviated DIA, dia, d, or ⌀, the definitions given above are only valid for circles, spheres and convex shapes. However, they are cases of a more general definition that is valid for any kind of n-dimensional convex or non-convex object. The diameter of a subset of a space is the least upper bound of the set of all distances between pairs of points in the subset. So, if A is the subset, the diameter is sup, if the distance function d is viewed here as having codomain R, this implies that the diameter of the empty set equals −∞. Some authors prefer to treat the empty set as a case, assigning it a diameter equal to 0. For any solid object or set of scattered points in n-dimensional Euclidean space, in medical parlance concerning a lesion or in geology concerning a rock, the diameter of an object is the supremum of the set of all distances between pairs of points in the object. In differential geometry, the diameter is an important global Riemannian invariant, the symbol or variable for diameter, ⌀, is similar in size and design to ø, the Latin small letter o with stroke. In Unicode it is defined as U+2300 ⌀ Diameter sign, on an Apple Macintosh, the diameter symbol can be entered via the character palette, where it can be found in the Technical Symbols category. The character will not display correctly, however, since many fonts do not include it. In many situations the letter ø is a substitute, which in Unicode is U+00F8 ø