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≡ (other)
The symbol ≡ (triple bar) is used in science and mathematics with several different meanings. It may refer to the following: Mathematics * Identity (mathematics), identity of two mathematical expressions * Logical biconditional, in logic (if and only if) * Modular arithmetic, a ≡ b (mod m) * Equivalence relation, often denoted using a triple bar Chemistry * Triple bond, a type of covalent bond between two atoms Computing * Hamburger button, often used for drop-down menus * Symbol for the line feed character in ISO 2047 ISO 2047 (Information processing – Graphical representations for the control characters of the 7-bit coded character set) is a standard for graphical representation of the control characters for debugging purposes, such as may be found in the ... Vehicles * Tesla Model 3, stylized symbol See also * ≅, a symbol used in Approximation#Typography, approximation * The eight trigrams of the Bagua: ☰, ☱, ☲, ☳, ☴, ☵, ☶, ☷ * Xi (le ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Triple Bar
The triple bar, or tribar ≡, is a symbol with multiple, context-dependent meanings. It has the appearance of an equals sign sign with a third line. The triple bar character in Unicode is code point .. The closely related code point is the same symbol with a slash through it, indicating the negation of its mathematical meaning. In LaTeX mathematical formulas, the code \equiv produces the triple bar symbol and \not\equiv produces the negated triple bar symbol as output. Uses Mathematics and philosophy In logic, it is used with two different but related meanings. It can refer to the if and only if connective, also called material equivalence. This is a binary operation whose value is true when its two arguments have the same value as each other. Alternatively, in some texts ⇔ is used with this meaning, while ≡ is used for the higher-level metalogical notion of logical equivalence, according to which two formulas are logically equivalent when all models give the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Identity (mathematics)
In mathematics, an identity is an equality relating one mathematical expression ''A'' to another mathematical expression ''B'', such that ''A'' and ''B'' (which might contain some variables) produce the same value for all values of the variables within a certain range of validity. In other words, ''A'' = ''B'' is an identity if ''A'' and ''B'' define the same functions, and an identity is an equality between functions that are differently defined. For example, (a+b)^2 = a^2 + 2ab + b^2 and \cos^2\theta + \sin^2\theta =1 are identities. Identities are sometimes indicated by the triple bar symbol instead of , the equals sign. Common identities Algebraic identities Certain identities, such as a+0=a and a+(-a)=0, form the basis of algebra, while other identities, such as (a+b)^2 = a^2 + 2ab +b^2 and a^2 - b^2 = (a+b)(a-b), can be useful in simplifying algebraic expressions and expanding them. Trigonometric identities Geometrically, trigonometric ide ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Logical Biconditional
In logic and mathematics, the logical biconditional, sometimes known as the material biconditional, is the logical connective (\leftrightarrow) used to conjoin two statements and to form the statement " if and only if ", where is known as the '' antecedent'', and the ''consequent''. This is often abbreviated as " iff ". Other ways of denoting this operator may be seen occasionally, as a double-headed arrow (↔ or ⇔ may be represented in Unicode in various ways), a prefixed E "E''pq''" (in Łukasiewicz notation or Bocheński notation), an equality sign (=), an equivalence sign (≡), or ''EQV''. It is logically equivalent to both (P \rightarrow Q) \land (Q \rightarrow P) and (P \land Q) \lor (\neg P \land \neg Q) , and the XNOR (exclusive nor) boolean operator, which means "both or neither". Semantically, the only case where a logical biconditional is different from a material conditional is the case where the hypothesis is false but the conclusion is true. In this case ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Modular Arithmetic
In mathematics, modular arithmetic is a system of arithmetic for integers, where numbers "wrap around" when reaching a certain value, called the modulus. The modern approach to modular arithmetic was developed by Carl Friedrich Gauss in his book ''Disquisitiones Arithmeticae'', published in 1801. A familiar use of modular arithmetic is in the 12-hour clock, in which the day is divided into two 12-hour periods. If the time is 7:00 now, then 8 hours later it will be 3:00. Simple addition would result in , but clocks "wrap around" every 12 hours. Because the hour number starts over at zero when it reaches 12, this is arithmetic ''modulo'' 12. In terms of the definition below, 15 is ''congruent'' to 3 modulo 12, so "15:00" on a 24-hour clock is displayed "3:00" on a 12-hour clock. Congruence Given an integer , called a modulus, two integers and are said to be congruent modulo , if is a divisor of their difference (that is, if there is an integer such that ). Congruence modulo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Equivalence Relation
In mathematics, an equivalence relation is a binary relation that is reflexive, symmetric and transitive. The equipollence relation between line segments in geometry is a common example of an equivalence relation. Each equivalence relation provides a partition of the underlying set into disjoint equivalence classes. Two elements of the given set are equivalent to each other if and only if they belong to the same equivalence class. Notation Various notations are used in the literature to denote that two elements a and b of a set are equivalent with respect to an equivalence relation R; the most common are "a \sim b" and "", which are used when R is implicit, and variations of "a \sim_R b", "", or "" to specify R explicitly. Non-equivalence may be written "" or "a \not\equiv b". Definition A binary relation \,\sim\, on a set X is said to be an equivalence relation, if and only if it is reflexive, symmetric and transitive. That is, for all a, b, and c in X: * a \sim a ( ref ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Triple Bond
A triple bond in chemistry is a chemical bond between two atoms involving six bonding electrons instead of the usual two in a covalent single bond. Triple bonds are stronger than the equivalent single bonds or double bonds, with a bond order of three. The most common triple bond, that between two carbon atoms, can be found in alkynes. Other functional groups containing a triple bond are cyanides and isocyanides. Some diatomic molecules, such as dinitrogen and carbon monoxide, are also triple bonded. In skeletal formulae the triple bond is drawn as three parallel lines (≡) between the two connected atoms. Bonding The types of bonding can be explained in terms of orbital hybridization. In the case of acetylene each carbon atom has two sp-orbitals and two p-orbitals. The two sp-orbitals are linear with 180° angles and occupy the x-axis ( cartesian coordinate system). The p-orbitals are perpendicular on the y-axis and the z-axis. When the carbon atoms approach each other, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hamburger Button
The hamburger button (the triple bar ≡ or trigram symbol ☰), so named for its unintentional resemblance to a hamburger, is a button typically placed in a top corner of a graphical user interface. Its function is to toggle a menu (sometimes referred to as a hamburger menu) or navigation bar between being collapsed behind the button or displayed on the screen. The icon which is associated with this widget, consisting of three horizontal bars, is also known as the ''collapsed menu icon''. History Original design The icon was originally designed by Norm Cox as part of the user interface for the Xerox Star, introduced in 1981; it saw a resurgence starting in 2009 stemming from the limited screen area available to mobile apps. Cox described the icon's creation, saying “Its graphic design was meant to be very “road sign” simple, functionally memorable, and mimic the look of the resulting displayed menu list. With so few pixels to work with, it had to be very distinct, ye ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Line Feed
Newline (frequently called line ending, end of line (EOL), next line (NEL) or line break) is a control character or sequence of control characters in character encoding specifications such as ASCII, EBCDIC, Unicode, etc. This character, or a sequence of characters, is used to signify the end of a line of text and the start of a new one. History In the mid-1800s, long before the advent of teleprinters and teletype machines, Morse code operators or telegraphists invented and used Morse code prosigns to encode white space text formatting in formal written text messages. In particular the Morse prosign (mnemonic reak ext) represented by the concatenation of literal textual Morse codes "B" and "T" characters sent without the normal inter-character spacing is used in Morse code to encode and indicate a ''new line'' or ''new section'' in a formal text message. Later, in the age of modern teleprinters, standardized character set control codes were developed to aid in white space ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ISO 2047
ISO 2047 (Information processing – Graphical representations for the control characters of the 7-bit coded character set) is a standard for graphical representation of the control characters for debugging purposes, such as may be found in the character generator of a computer terminal; it also establishes a two-letter abbreviation of each control character. It started out as ANSI X3.32-1973 (American National Standard – Graphic Representation of the Control Characters of American National Standard Code for Information Interchange in 1973 and became an ISO standard in 1975. In addition, "Character Mnemonics & Character Sets" is cited as the ISO 2047 two-letter abbreviation of the control character. ISO 2047, ECMA-17 [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tesla Model 3
The Tesla Model 3 is a compact executive sedan that is battery powered and produced by Tesla. Limited production of the Model 3 began in mid-2017, with the first production vehicle rolling off the assembly line on July 7, 2017. The official launch and delivery of the first 30 cars took place on July 28. The base Model 3 delivers an EPA-rated all-electric range of and the Long Range version delivers . According to Tesla, the Model 3 carries full self-driving hardware, with periodic software updates adding functionality. The Model 3 was marketed as being more affordable to more people than previous models by Tesla. Since early 2020, the Model 3 is the bestselling electric car in world history, and, in June 2021, became the first electric car to pass the 1 million global sales milestone. The Model 3 has been the world's top selling plug-in electric car (PEV) for three years running, from 2018 to 2020. It has also been the bestselling PEV in the United States for three ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Approximation
An approximation is anything that is intentionally similar but not exactly equality (mathematics), equal to something else. Etymology and usage The word ''approximation'' is derived from Latin ''approximatus'', from ''proximus'' meaning ''very near'' and the prefix ''ad-'' (''ad-'' before ''p'' becomes ap- by assimilation (phonology), assimilation) meaning ''to''. Words like ''approximate'', ''approximately'' and ''approximation'' are used especially in technical or scientific contexts. In everyday English, words such as ''roughly'' or ''around'' are used with a similar meaning. It is often found abbreviated as ''approx.'' The term can be applied to various properties (e.g., value, quantity, image, description) that are nearly, but not exactly correct; similar, but not exactly the same (e.g., the approximate time was 10 o'clock). Although approximation is most often applied to numbers, it is also frequently applied to such things as Function (mathematics), mathematical functio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bagua
The bagua or pakua (八卦) are a set of eight symbols that originated in China, used in Taoist cosmology to represent the fundamental principles of reality, seen as a range of eight interrelated concepts. Each consists of three lines, each line either "broken" or "unbroken", respectively representing yin or yang. Due to their tripartite structure, they are often referred to as Eight Trigrams in English. The trigrams are related to Taiji philosophy, Taijiquan and the Wuxing, or "five elements". The relationships between the trigrams are represented in two arrangements: the ''Primordial'' (), "Earlier Heaven", or "Fu Xi" bagua () and the ''Manifested'' (), "Later Heaven", or "King Wen" bagua. The trigrams have correspondences in astronomy, astrology, geography, geomancy, anatomy, the family, martial arts, Chinese medicine and elsewhere. The ancient Chinese classic, I Ching (Pinyin: Yi Jing), consists of the 64 pairwise permutations of trigrams, referred to as " hexagrams", a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
