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