Reciprocity may refer to:

Law and trade

Reciprocity (Canadian politics) Reciprocity, in 19th- and early 20th-century Canadian politics, meant free trade, the removal of protective tariffs on all natural resources between Canada and the United States. Reciprocity and free trade have been emotional issues in Canadian ...

, free trade with the United States of America **

Reciprocal trade agreement A trade agreement (also known as trade pact) is a wide-ranging taxes, tariff and trade treaty that often includes investment guarantees. It exists when two or more countries agree on terms that help them trade with each other. The most common tr ...

, 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 Article IV, Section 1 of the United States Constitution, the Full Faith and Credit Clause, addresses the duty that states within the United States have to respect the "public acts, records, and judicial proceedings of every other state." Acc ...

, which provides for it **

Occupational licensing Occupational licensing, also called occupational licensure, is a form of government regulation requiring a license to pursue a particular profession or vocation for compensation. It is related to occupational closure. Professions that can have ...

, 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 The norm of reciprocity requires that we repay in kind what another has done for us.Whatley, M, A., Rhodes, A., Smith, R. H., Webster, J. M. (1999) ''The Effect of a Favor on Public and Private Compliance: How Internalized is the Norm of Reciprocit ...

, social norm of in-kind responses to the behavior of others *

Reciprocity (cultural anthropology) In cultural anthropology, reciprocity refers to the non-market exchange of goods or labour ranging from direct barter (immediate exchange) to forms of gift exchange where a return is eventually expected (delayed exchange) as in the exchange of bi ...

, way of defining people's informal exchange of goods and labour *

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. A corollary is how a desire for revenge can harm the collective ...

, mechanisms for the evolution of cooperation *

Reciprocity (international relations) In international relations and treaties, the principle of reciprocity states that favors, benefits, or penalties that are granted by one state to the citizens or legal entities of another, should be returned in kind. For example, reciprocity has b ...

, 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) 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 wit ...

, concept of reciprocity as in-kind positive or negative responses for the actions of others *

Reciprocity (social psychology) In social psychology, reciprocity is a social norm of responding to a positive action with another positive action, rewarding kind actions. As a social construct, reciprocity means that in response to friendly actions, people are frequently much ni ...

, 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) In classical electromagnetism, reciprocity refers to a variety of related theorems involving the interchange of time-harmonic electric current densities (sources) and the resulting electromagnetic fields in Maxwell's equations for time-invariant ...

, 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) Optoelectronic reciprocity relations relate properties of a diode under illumination to the photon emission of the same diode under applied voltage. The relations are useful for interpretation of luminescence based measurements of solar cells and m ...

, a diode under illumination to the photon emission of the same diode under applied voltage *

Reciprocity (photography) In photography, reciprocity is 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 t ...

, 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 The Helmholtz reciprocity principle describes how a ray of light and its reverse ray encounter matched optical adventures, such as reflections, refractions, and absorptions in a passive medium, or at an interface. It does not apply to moving, non ...

, linear propagation.

Mathematics

Reciprocity law In mathematics, a reciprocity law is a generalization of the law of quadratic reciprocity to arbitrary monic irreducible polynomials f(x) with integer coefficients. Recall that first reciprocity law, quadratic reciprocity, determines when an ir ...

(law of reciprocity) in mathematics, including **

Quadratic reciprocity In number theory, the law of quadratic reciprocity is a theorem about modular arithmetic that gives conditions for the solvability of quadratic equations modulo prime numbers. Due to its subtlety, it has many formulations, but the most standard st ...

, a fundamental result in number theory **

Cubic reciprocity Cubic reciprocity is a collection of theorems in elementary and algebraic number theory that state conditions under which the congruence ''x''3 ≡ ''p'' (mod ''q'') is solvable; the word "reciprocity" comes from the form of ...

, theorems that state conditions under which the congruence is solvable **

Quartic reciprocity Quartic or biquadratic reciprocity is a collection of theorems in elementary and algebraic number theory that state conditions under which the congruence ''x''4 ≡ ''p'' (mod ''q'') is solvable; the word "reciprocity" comes from the form o ...

, a collection of theorems in elementary and algebraic number theory that state conditions under which the congruence is solvable **

Artin reciprocity law The Artin reciprocity law, which was established by Emil Artin in a series of papers (1924; 1927; 1930), is a general theorem in number theory that forms a central part of global class field theory. The term "reciprocity law" refers to a long line ...

, 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 Methods of computing square roots are numerical analysis algorithms for approximating the principal, or non-negative, square root (usually denoted \sqrt, \sqrt /math>, or S^) of a real number. Arithmetically, it means given S, a procedure for fin ...

Reciprocity (projective geometry) In projective geometry, a correlation is a transformation of a ''d''-dimensional projective space that maps Projective space#Projective subspace, subspaces of dimension ''k'' to subspaces of dimension , reversing Inclusion (set theory), inclusion ...

, a collineation from a projective space onto its dual space, taking points to hyperplanes (and vice versa) and preserving incidence *

Frobenius reciprocity In mathematics, and in particular representation theory, Frobenius reciprocity is a theorem expressing a duality between the process of restricting and inducting. It can be used to leverage knowledge about representations of a subgroup to find ...

, from group representation theory * Reciprocity law for Dedekind sums *

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 (defined below) and the generatin ...

, 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 In mathematics, Hermite's law of reciprocity, introduced by , states that the degree ''m'' covariants of a binary form of degree ''n'' correspond to the degree ''n'' covariants of a binary form of degree ''m''. In terms of representation theory ...

for invariants of binary forms.

Other

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

Law and trade

Social sciences and humanities

Physical sciences and engineering

Mathematics

Other

See also