Reciprocity

Reciprocity may refer to:

Law and trade

• Reciprocity (Canadian politics), 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
• Interstate reciprocity, recognition of sibling federated states' laws:
  • In the United States specifically:
    • Full Faith and Credit Clause, which provides for it
    • Concealed carry reciprocity
  • Occupational licensing, which in some jurisdictions provides for it
• Traffic violations reciprocity where non-resident drivers are treated like residents
• Quid pro quo, a legal concept of the exchange of good or services, each having value

Social sciences and humanities

• Norm of reciprocity, social norm of in-kind responses to the behavior of others
• Reciprocity (cultural anthropology), way of defining people's informal exchange of goods and labour
• Reciprocity (evolution), mechanisms for the evolution of cooperation
• Reciprocity (international relations), 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), concept of reciprocity as in-kind positive or negative responses for the actions of others
• Reciprocity (social psychology), in-kind positively or negatively connoted responses of individuals towards the actions of others
• Ethic of reciprocity (the Golden Rule), that one should treat others as one would like others to treat oneself
• Serial reciprocity, in which the benefactor of a gift or service will in turn provide benefits to a third party

Physical sciences and engineering

• Reciprocity (engineering), used in the analysis of structures and to resolve complex load conditions
• Reciprocity (electromagnetism), theorems relating sources and the resulting fields in classical electromagnetism
• Reciprocity (electrical networks), reciprocity theorem as it relates to current and voltage in electrical networks
• Reciprocity (network science), measures the tendency of vertex pairs to form mutual connections between each other
• Reciprocity (optoelectronic), a diode under illumination to the photon emission of the same diode under applied voltage
• Reciprocity (photography), the relationship between the intensity of the light and duration of the exposure that result in identical exposure
• Reciprocity of twist and wrench, in screw theory
• Reciprocity theorem (disambiguation), several unrelated results
• Reciprocity of antenna transmitting and receiving characteristics
• Helmholtz reciprocity, linear propagation.

Mathematics

• Reciprocity law (law of reciprocity) in mathematics, including
  • Quadratic reciprocity, a fundamental result in number theory
  • Cubic reciprocity, theorems that state conditions under which the congruence x³ ≡ p (mod q) is solvable
  • Quartic reciprocity, 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 law, a general theorem in number theory that provided a partial solution to Hilbert's ninth problem
  • Reciprocity relation or exact differential, a mathematical differential of the form dQ, for some differentiable function Q
• Weil reciprocity law
• Reciprocal polynomials, the coefficients of the remainder polynomial are the bits of the CRC
• Reciprocal square root
• Reciprocity (projective geometry), a collineation from a projective space onto its dual space, taking points to hyperplanes (and vice versa) and preserving incidence
• Frobenius reciprocity, from group representation theory
• Reciprocity law for Dedekind sums
• Stanley's reciprocity theorem, 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
• Hermite reciprocity for invariants of binary forms.

Other

• Reciprocity (Fringe), a 2011 episode of the television series Fringe
• Rural Municipality of Reciprocity No. 32, Saskatchewan, Canada

See also

• Reciprocal (disambiguation)
• Reciprocation (disambiguation)
• Reciprocity Treaty (disambiguation)
• Reciprocal altruism between individuals of different species
• Meeting of the minds in contract law, sometimes called reciprocity
• Tit for tat