Duality may refer to:

Mathematics

* Duality (mathematics), a mathematical concept ** Dual (category theory), 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), a concept regarding binary relations **

Duality (projective geometry) In geometry, a striking feature of projective planes is the symmetry of the roles played by points and lines in the definitions and theorems, and (plane) duality is the formalization of this concept. There are two approaches to the subject of dua ...

, general principle of projective geometry **

Duality principle (Boolean algebra) In mathematics and mathematical logic, Boolean algebra is a branch of algebra. It differs from elementary algebra in two ways. First, the values of the variables are the truth values ''true'' and ''false'', usually denoted 1 and 0, whereas in ...

, the extension of order-theoretic duality to Boolean algebras ** S-duality (homotopy theory) *

Philosophy, logic, and psychology

Dualistic cosmology Dualism in cosmology or dualistic cosmology is the moral or spiritual 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 traditi ...

, a twofold division in several spiritual and religious worldviews * Dualism (philosophy of mind), where the body and mind are considered to be irreducibly distinct * De Morgan's laws, specifically the ability to generate the dual of any logical expression * Complementary duality of Carl Jung's functions and types in Socionics

Science

Electrical and mechanical

* Duality (electrical circuits), regarding isomorphism of electrical circuits * Duality (mechanical engineering), regarding isomorphism of some mechanical laws

Physics

AdS/CFT correspondence In theoretical physics, the anti-de Sitter/conformal field theory correspondence, sometimes called Maldacena duality or gauge/gravity duality, is a conjectured relationship between two kinds of physical theories. On one side are anti-de Sitter s ...

(anti de Sitter/conformal field theory correspondence), sometimes called the Maldacena duality *

Dual resonance model In theoretical physics, a dual resonance model arose during the early investigation (1968–1973) of string theory as an S-matrix theory of the strong interaction. Overview The dual resonance model was based upon the observation that the amplitud ...

* 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 Hendrik ...

* * Mirror symmetry (string theory) *

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 magne ...

* Mysterious duality * String duality, a class of symmetries ** S-duality ** T-duality ** U-duality *

Wave–particle duality Wave–particle duality is the concept in quantum mechanics that every particle or quantum entity may be described as either a particle or a wave. It expresses the inability of the classical concepts "particle" or "wave" to fully describe the ...

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'', a 2009 album by

Darker Half Darker-half is a heavy metal band from Sydney, led by vocalist Vo Simpson and known for their energetic live performances, their style has been described as power/thrash. History Singer/guitarist Vo Simpson started Darker Half in 2003 whi ...

* ''Duality'', a 2020 album by

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

* ''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 & Grammy-nominated song 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 *

Duality (CoPs) In the theory of community of practice, an interdisciplinary field between sociology of education and educational psychology, the notion of a duality is used to capture the idea of the tension between two opposing forces which become a driving f ...

, refers to the notion of a duality in a Community of Practice * Dual (grammatical number), grammatical number that some languages use in addition to singular and plural