• Reciprocity (Canadian politics)
  Reciprocity (Canadian politics)
  In nineteenth and early twentieth century Canadian politics, the term reciprocity was used to describe the concept of free trade with the United States of America...
  
  , used to describe the concept of free trade with the United States of America
  • Reciprocal trade agreement, entered into in order to reduce (or eliminate) tariffs, quotas and other trade restrictions on items traded between the signatories
• Reciprocity (photography)
  Reciprocity (photography)
  In photography reciprocity refers to the inverse relationship between the intensity and duration of light that determines the reaction of light-sensitive material. Within a normal exposure range for film stock, for example, the reciprocity law states that the film response will be determined by the...
  
  , the relationship between the intensity of the light and duration of the exposure that result in identical exposure
• Traffic violations reciprocity
  Traffic Violations Reciprocity
  Under traffic violations reciprocity agreements, non-resident drivers are treated like residents when they are stopped for a traffic offense that occurs in another jurisdiction. They also ensure that punishments such as "points" on one's license and the ensuring increase in insurance premiums...
  
   where non-resident drivers are treated like residents
• Reciprocity (Fringe)
  Reciprocity (Fringe)
  "Reciprocity" is the 11th episode of the third season of the American science fiction drama television series Fringe, and the 54th episode overall. The episode has the Fringe division following a chain of shapeshifter murders as the assembly of the doomsday device nears completion.Josh Singer wrote...
  
  , a 2011 episode of the television series Fringe

Social sciences and humanities

• The Golden Rule/ethic of reciprocity
  Ethic of reciprocity
  The Golden Rule or ethic of reciprocity is a maxim, ethical code, or moralitythat essentially states either of the following:* : One should treat others as one would like others to treat oneself....
  
  
• Norm of reciprocity
  Norm of reciprocity
  The norm of reciprocity is the social expectation that people will respond to each other in kind—returning benefits for benefits, and responding with either indifference or hostility to harms. The social norm of reciprocity often takes different forms in different areas of social life, or in...
  
  , social norm of in-kind responses to the behavior of others
• Reciprocity (cultural anthropology)
  Reciprocity (cultural anthropology)
  In cultural anthropology and sociology, reciprocity is a way of defining people's informal exchange of goods and labour; that is, people's informal economic systems. It is the basis of most non-market economies. Since virtually all humans live in some kind of society and have at least a few...
  
  , way of defining people's informal exchange of goods and labour
• Reciprocity (evolution)
  Reciprocity (evolution)
  Reciprocity in evolutionary biology refers to mechanisms whereby the evolution of cooperative or altruistic behaviour may be favoured by the probability of future mutual interactions...
  
  , mechanisms for the evolution of cooperation
• Reciprocity (international relations)
  Reciprocity (international relations)
  In international relations and treaties, the principle of reciprocity states that favours, benefits, or penalties that are granted by one state to the citizens or legal entities of another, should be returned in kind....
  
  , principle that favours, benefits, or penalties that are granted by one state to the citizens or legal entities of another, should be returned in kind
• Reciprocity (social and political philosophy)
  Reciprocity (social and political philosophy)
  The social norm of reciprocity is the expectation that people will respond to each other in similar ways—responding to gifts and kindnesses from others with similar benevolence of their own, and responding to harmful, hurtful acts from others with either indifference or some form of retaliation...
  
  , concept of reciprocity as in-kind positive or negative responses for the actions of others; relation to justice; related ideas such as gratitude, mutuality, and The Golden Rule (Ethic of reciprocity
  Ethic of reciprocity
  The Golden Rule or ethic of reciprocity is a maxim, ethical code, or moralitythat essentially states either of the following:* : One should treat others as one would like others to treat oneself....
  
  }
• Reciprocity (social psychology)
  Reciprocity (social psychology)
  Reciprocity in social psychology refers to responding to a positive action with another positive action, rewarding kind actions. People categorize an action as kind by viewing its consequences and also by the person's fundamental intentions. Even if the consequences are the same, underlying...
  
  , in-kind positively or negatively connotated responses of individuals towards the actions of others
• Serial reciprocity, where the benefactor of a gift or service will in turn provide benefits to a third party

Natural sciences

• Reciprocity (engineering)
  Reciprocity (engineering)
  Reciprocity in linear systems is the principle that a response Rab, measured at a location a, when the system has an excitation signal applied at a location b, is exactly equal to Rba which is the response at location b, when that same excitation is applied at a...
  
  ,  = Hba, if the system is linear
• Reciprocity (electromagnetism)
  Reciprocity (electromagnetism)
  In classical electromagnetism, reciprocity refers to a variety of related theorems involving the interchange of time-harmonic electric current densities and the resulting electromagnetic fields in Maxwell's equations for time-invariant linear media under certain constraints...
  
  , theorems relating sources and the resulting fields in classical electromagnetism
• Reciprocity (network theory), theorem about transfer function of passive networks
• Reciprocity in network
  Reciprocity in network
  Theoretical efforts have been made to study the nontrivial properties of complex networks, such as clustering, scale-free degree distribution, community structures, etc. Here Reciprocity is another quantity to specifically characterize directed networks. Link reciprocity measures the tendency of...
  
  , measures the tendency of vertex pairs to form mutual connections between each other
• Reciprocity of twist and wrench, in screw theory
• Reciprocity theorem (disambiguation), several unrelated results

Mathematics

• Reciprocity law
  Reciprocity law
  In mathematics, a reciprocity law is a generalization of the law of quadratic reciprocity.There are several different ways to express reciprocity laws...
  
   in mathematics, including
  • Quadratic reciprocity
    Quadratic reciprocity
    In number theory, the law of quadratic reciprocity is a theorem about modular arithmetic which gives conditions for the solvability of quadratic equations modulo prime numbers...
    
    , a fundamental result in number theory
  • cubic reciprocity
    Cubic reciprocity
    Cubic reciprocity is a collection of theorems in elementary and algebraic number theory that state conditions under which the congruence x3 ≡ p  is solvable; the word "reciprocity" comes from the form of the main theorem, which states that if p and q are primary numbers in the...
    
    , theorems that state conditions under which the congruence x3 ≡ p (mod q) is solvable
  • quartic reciprocity
    Quartic reciprocity
    Quartic or biquadratic reciprocity is a collection of theorems in elementary and algebraic number theory that state conditions under which the congruence x4 ≡ p is solvable; the word "reciprocity" comes from the form of some of these theorems, in that they relate the solvability of the...
    
    , a collection of theorems in elementary and algebraic number theory that state conditions under which the congruence x4 ≡ p (mod q) is solvable
  • Artin reciprocity
    Artin reciprocity
    The Artin reciprocity law, established by Emil Artin in a series of papers , is a general theorem in number theory that forms a central part of the global class field theory...
    
    
  • Reciprocity relation or Exact differential, a mathematical differential of the form dQ, for some differentiable function Q
• Weil reciprocity for algebraic curves
• Reciprocal polynomials, the coefficients of the remainder polynomial are the bits of the CRC
• Reciprocal square root
• Reciprocity (projective geometry)
  Reciprocity (projective geometry)
  A reciprocity is a collineation from a projective space onto its dual space, taking points to hyperplanes and preserving incidence.If it can be represented as a homography, it is called a correlation....
  
  , a collineation from a projective space onto its dual space, taking points to hyperplanes (and vice versa) and preserving incidence

Theorems

• Frobenius reciprocity
• Reciprocity law for Dedekind sums
• Stanley's reciprocity theorem
  Stanley's reciprocity theorem
  In combinatorial mathematics, Stanley's reciprocity theorem, named after MIT mathematician Richard P. Stanley, states that a certain functional equation is satisfied by the generating function of any rational cone and the generating function of the cone's interior.A rational cone is the set of all...
  
  , states that a certain functional equation is satisfied by the generating function of any rational cone and the generating function of the cone's interior

See also

• Mutual assent in Contract law, sometimes called Reciprocity
• Symbiosis
  Symbiosis
  Symbiosis is close and often long-term interaction between different biological species. In 1877 Bennett used the word symbiosis to describe the mutualistic relationship in lichens...
  
  , an interaction between two organisms living together in more or less intimate association
• Reciprocal (disambiguation)
• Reciprocation (disambiguation)
• Reciprocity Treaty (disambiguation)
• Double standard
  Double standard
  A double standard is the unjust application of different sets of principles for similar situations. The concept implies that a single set of principles encompassing all situations is the desirable ideal. The term has been used in print since at least 1895...
  
  , the unjust application of different sets of principles for similar situations
• Hypocrisy
  Hypocrisy
  Hypocrisy is the state of pretending to have virtues, moral or religious beliefs, principles, etc., that one does not actually have. Hypocrisy involves the deception of others and is thus a kind of lie....
  
  , the state of pretending to have virtues, moral or religious beliefs, principles, etc., that one does not actually have