Mathematics

• Duality (mathematics)
  Duality (mathematics)
  In mathematics, a duality, generally speaking, translates concepts, theorems or mathematical structures into other concepts, theorems or structures, in a one-to-one fashion, often by means of an involution operation: if the dual of A is B, then the dual of B is A. As involutions sometimes have...
  
  , a mathematical concept
  • Dual (category theory)
    Dual (category theory)
    In category theory, a branch of mathematics, duality is a correspondence between properties of a category C and so-called dual properties of the opposite category Cop...
    
    , a formalization of mathematical duality
  • Duality (order theory)
    Duality (order theory)
    In the mathematical area of order theory, every partially ordered set P gives rise to a dual partially ordered set which is often denoted by Pop or Pd. This dual order Pop is defined to be the set with the inverse order, i.e. x ≤ y holds in Pop if and only if y ≤ x holds in P...
    
    , a concept regarding binary relations
  • Duality (projective geometry)
    Duality (projective geometry)
    A striking feature of projective planes is the "symmetry" of the roles played by points and lines in the definitions and theorems, and duality is the formalization of this metamathematical concept. There are two approaches to the subject of duality, one through language and the other a more...
    
    , general principle of projective geometry
  • S-duality (homotopy theory)
  • Dual problem
    Dual problem
    In constrained optimization, it is often possible to convert the primal problem to a dual form, which is termed a dual problem. Usually dual problem refers to the Lagrangian dual problem but other dual problems are used, for example, the Wolfe dual problem and the Fenchel dual problem...
    
    
• List of dualities (Mathematics)

Philosophy, logic, and psychology

• Dualism
  Dualism
  Dualism denotes a state of two parts. The term 'dualism' was originally coined to denote co-eternal binary opposition, a meaning that is preserved in metaphysical and philosophical duality discourse but has been diluted in general or common usages. Dualism can refer to moral dualism, Dualism (from...
  
  , a twofold division in several spiritual, religious, and philosophical doctrines
• Dualism (philosophy of mind)
  Dualism (philosophy of mind)
  In philosophy of mind, dualism is a set of views about the relationship between mind and matter, which begins with the claim that mental phenomena are, in some respects, non-physical....
  
  , 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.

Electrical and mechanical

• Duality (electrical circuits), regarding isomorphism of electrical circuits
• Duality (mechanical engineering)
  Duality (mechanical engineering)
  In mechanical engineering, many terms are associated into pairs called duals. A dual of a relationship is formed by interchanging force and deformation in an expression.Here is a partial list of mechanical dualities:...
  
  , regarding isomorphism of some mechanical laws

Physics

• AdS/CFT correspondence
  AdS/CFT correspondence
  In physics, the AdS/CFT correspondence , sometimes called the Maldacena duality, is the conjectured equivalence between a string theory and gravity defined on one space, and a quantum field theory without gravity defined on the conformal boundary of this space, whose dimension is lower by one or more...
  
  , (anti de Sitter/conformal field theory correspondence), sometimes called the Maldacena duality
• Dual resonance model
  Dual resonance model
  In theoretical physics, a dual resonance model arose the early investigation of string theory as an S-matrix theory of the strong interaction....
  
  
• Duality (electricity and magnetism)
• Englert–Greenberger duality relation
• Holographic duality
• Kramers–Wannier duality
• List of dualities (physics)
• Mirror symmetry
  Mirror symmetry
  In physics and mathematics, mirror symmetry is a relation that can exist between two Calabi-Yau manifolds. It happens, usually for two such six-dimensional manifolds, that the shapes may look very different geometrically, but nevertheless they are equivalent if they are employed as hidden...
  
  
• Montonen–Olive duality
• Mysterious duality
• String duality
  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....
  
   is a class of symmetries
• S-duality
  S-duality
  In theoretical physics, S-duality is an equivalence of two quantum field theories or string theories. An S-duality transformation maps states and vacua with coupling constant g in one theory to states and vacua with coupling constant 1/g in the dual theory...
  
  
• T-duality
  T-duality
  T-duality is a symmetry of quantum field theories with differing classical descriptions, of which the relationship between small and large distances in various string theories is a special case. Discussion of the subject originated in a paper by T. S. Buscher and was further developed by Martin...
  
  
• U-duality
  U-duality
  In physics, U-duality 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 the "U-duality group" of M-theory as defined on a particular background space . This is the union of all the S- and T-dualities...
  
  
• Wave–particle duality
  Wave–particle duality
  Wave–particle duality postulates that all particles exhibit both wave and particle properties. A central concept of quantum mechanics, this duality addresses the inability of classical concepts like "particle" and "wave" to fully describe the behavior of quantum-scale objects...
  
  

Film

• Duality (film)
  Duality (film)
  Duality is a Star Wars fan film created by Mark Thomas and Dave Macomber that made its debut on the internet on February 10, 2001. It is one of the first fan films to exclusively use bluescreen footage composited onto virtual backgrounds.-Plot:...
  
  , a Star Wars fan film by Dave Macomber and Mark Thomas

Music

• Duality (Lisa Gerrard & Pieter Bourke album), a 1998 album by Lisa Gerrard and Pieter Bourke
• Duality (song)
  Duality (song)
  "Duality" is a song by the American heavy metal band Slipknot, the song was released as the first single from their third album Vol. 3: , released in 2004...
  
  , a 2004 single & Grammy-nominated song by metal band Slipknot
• Duality (Ra album)
  Duality (Ra album)
  Duality is a 2005 album from the band Ra. The style from this album has noticeably changed since Ra's debut album of "From One". The album boasts a hard rock and medolic vibe whereas their first album had more of a nu-metal feel. The middle-eastern influences in the CD are still present, but are...
  
  , a 2005 album by the rock band Ra
• Duality, a 2007 single from alternative rock/punk band Bayside
  Bayside (band)
  Bayside is an American punk rock band from Queens which formed in the winter of 2000. The band has released five full length albums since signing to Victory Records...
  
  

Other

• Duality, a large format audio mixing console by Solid State Logic
• Duality (CoPs)
  Duality (CoPs)
  In the context of a Community of practice the notion of a duality is used to capture the idea of the tension between two opposing 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...
  
   refers to the notion of a duality in a Community of Practice
• Dual (grammatical number)
  Dual (grammatical number)
  Dual 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 identified by the noun or pronoun...
  
   grammatical number that some languages use in addition to singular and plural

See also

• Double (disambiguation)
• Dual (disambiguation)
• Duality principle (disambiguation)
• List of dualities: Philosophy, Mathematics, Physics and Engineering
• Nondualism
  Nondualism
  Nondualism is a term used to denote affinity, or unity, rather than duality or separateness or multiplicity. In reference to the universe it may be used to denote the idea that things appear distinct while not being separate. The term "nondual" can refer to a belief, condition, theory, practice,...
  
   (Philosophy)
• Triality
  Triality
  In mathematics, triality is a relationship between three vector spaces, analogous to the duality relation between dual vector spaces. Most commonly, it describes those special features of the Dynkin diagram D4 and the associated Lie group Spin, the double cover of 8-dimensional rotation group SO,...
  
  (Mathematics)