Duality may refer to:

Mathematics

Duality (mathematics) In mathematics, a duality translates concepts, theorems or mathematical structures into other concepts, theorems or structures in a one-to-one fashion, often (but not always) by means of an involution operation: if the dual of is , then the ...

, a mathematical concept **

Dual (category theory) In category theory, a branch of mathematics, duality is a correspondence between the properties of a category ''C'' and the dual properties of the opposite category ''C''op. Given a statement regarding the category ''C'', by interchanging the s ...

, a formalization of mathematical duality **

Duality (optimization) In mathematical optimization theory, duality or the duality principle is the principle that optimization problems may be viewed from either of two perspectives, the primal problem or the dual problem. If the primal is a minimization problem then th ...

Duality (order theory) In the mathematical area of order theory, every partially ordered set ''P'' gives rise to a dual (or opposite) partially ordered set which is often denoted by ''P''op or ''P'd''. This dual order ''P''op is defined to be the same set, but with ...

, a concept regarding binary relations **

Duality (projective geometry) In projective geometry, duality or plane duality is a formalization of the striking symmetry of the roles played by Point (geometry), points and Line (geometry), lines in the definitions and theorems of projective planes. There are two approaches ...

, general principle of projective geometry ** Duality principle (Boolean algebra), the extension of order-theoretic duality to Boolean algebras ** S-duality (homotopy theory) *

Philosophy, logic, and psychology

Dualistic cosmology Dualism or dualistic cosmology is the moral or belief that two fundamental concepts exist, which often oppose each other. It is an umbrella term that covers a diversity of views from various religions, including both traditional religions and scri ...

, a twofold division in several spiritual and religious worldviews *

Dualism (philosophy of mind) Dualism most commonly refers to: * Mind–body dualism, a philosophical view which holds that mental phenomena are, at least in certain respects, not physical phenomena, or that the mind and the body are distinct and separable from one another * ...

, where the body and mind are considered to be irreducibly distinct *

De Morgan's laws In propositional calculus, propositional logic and Boolean algebra, De Morgan's laws, also known as De Morgan's theorem, are a pair of transformation rules that are both Validity (logic), valid rule of inference, rules of inference. They are nam ...

, specifically the ability to generate the dual of any logical expression * Complementary duality of Carl Jung's functions and types in

Socionics In psychology and sociology, socionics is a pseudoscientific theory of information processing and personality types. It incorporates Carl Jung's work on ''Psychological Types'' with Antoni Kępiński's theory of information metabolism. In contr ...

Duality (CoPs) In a community of practice, duality refers to a tension between two forces which become a driving force for change and creativity. Wenger uses the concept of dualities to examine the forces that create and sustain a community of practice. He de ...

, refers to the notion of a duality in a Community of Practice

Science

Electrical and mechanical

Duality (electrical circuits) In electrical engineering, electrical terms are associated into pairs called duals. A dual of a relationship is formed by interchanging voltage and Electric current, current in an expression. The dual expression thus produced is of the same form ...

, regarding isomorphism of electrical circuits *

Duality (mechanical engineering) In mechanical engineering, many terms are associated into pairs called duals. A dual of a relationship is formed by interchanging force (stress) and deformation (strain) in an expression. Here is a partial list of mechanical dualities: * force & ...

, regarding isomorphism of some mechanical laws

Physics

AdS/CFT correspondence In theoretical physics, the anti-de Sitter/conformal field theory correspondence (frequently abbreviated as AdS/CFT) is a conjectured relationship between two kinds of physical theories. On one side are anti-de Sitter spaces (AdS) that are used ...

(anti de Sitter/conformal field theory correspondence), sometimes called the Maldacena duality * Dual resonance model * Duality (electricity and magnetism) * Englert–Greenberger duality relation * Holographic duality *

Kramers–Wannier duality The Kramers–Wannier duality is a symmetry in statistical physics. It relates the free energy of a two-dimensional square-lattice Ising model at a low temperature to that of another Ising model at a high temperature. It was discovered by Hendr ...

* *

Mirror symmetry (string theory) In algebraic geometry and theoretical physics, mirror symmetry is a relationship between geometry, geometric objects called Calabi–Yau manifolds. The term refers to a situation where two Calabi–Yau manifolds look very different geometrically ...

Montonen–Olive duality Montonen–Olive duality or electric–magnetic duality is the oldest known example of strong–weak duality or S-duality according to current terminology. It generalizes the electro-magnetic symmetry of Maxwell's equations by stating that magn ...

Mysterious duality In physics, M-theory is a theory that unifies all Consistency, consistent versions of superstring theory. Edward Witten first conjectured the existence of such a theory at a string theory conference at the University of Southern California in 1 ...

String duality String duality is a class of symmetries in physics that link different string theories, theories which assume that the fundamental building blocks of the universe are strings instead of point particles. Overview Before the so-called "duality r ...

, a class of symmetries **

S-duality In theoretical physics, S-duality (short for strong–weak duality, or Sen duality) is an equivalence of two physical theories, which may be either quantum field theories or string theories. S-duality is useful for doing calculations in theore ...

T-duality T-duality (short for target-space duality) in theoretical physics is an equivalence of two physical theories, which may be either quantum field theories or string theories. In the simplest example of this relationship, one of the theories descr ...

U-duality In physics, U-duality (short for unified duality)S. Mizoguchi,On discrete U-duality in M-theory, 2000. is a symmetry of string theory or M-theory combining S-duality and T-duality transformations. The term is most often met in the context of th ...

Wave–particle duality Wave–particle duality is the concept in quantum mechanics that fundamental entities of the universe, like photons and electrons, exhibit particle or wave (physics), wave properties according to the experimental circumstances. It expresses the in ...

Music

Albums

* ''Duality'' (Peter Leitch and John Hicks album), 1994 * ''Duality'' (Lisa Gerrard and Pieter Bourke album), 1998 * ''Duality'' (Set It Off album), 2014 * ''Duality'' (Ra album), 2005 * ''Duality'' (mixtape), 2012 * ''Duality'' (Luna Li album), 2022 * ''Duality'' (Lindsey Stirling album), 2024 * ''Duality'', a 2009 album by Darker Half * ''Duality'', a 2020 album by

Duke Dumont Adam George Dyment (born 27 August 1981), better known by his stage name Duke Dumont, is an English DJ and music producer. He is best known for his hit singles "Need U (100%)", "I Got U", "Won't Look Back (song), Won't Look Back" and "Ocean Dr ...

* ''Duality'', a 2018 album by Big Scoob

Songs

* "Duality", a 2014 single from pop rock/punk rock band Set It Off * "Duality" (song), a 2004 single by metal band Slipknot * "Duality", a 2007 single from alternative rock/punk band Bayside

Other

* ''Duality'' (film), a 2001 Star Wars fan film by Dave Macomber and Mark Thomas * Duality, a large format audio mixing console by

Solid State Logic Solid State Logic Ltd. (SSL) is a British company based in Begbroke, Oxfordshire, England that designs and markets audio mixing consoles, Audio signal processing, signal processors, and other audio technologies for the post-production, video p ...

Dual (grammatical number) Dual ( abbreviated ) is a grammatical number that some languages use in addition to singular and plural. When a noun or pronoun appears in dual form, it is interpreted as referring to precisely two of the entities (objects or persons) identifie ...

, grammatical number that some languages use in addition to singular and plural