Jacobi symbol
Noun
Meaning
Jacobi symbol (plural Jacobi symbols)
(number theory) A mathematical function of integer a and odd positive integer b, generally written
(
a
b
)
{\displaystyle \left({a \over b}\right)}
, based on, for each of the prime factors pi of b, whether a is a quadratic residue or nonresidue modulo pi.
Examples
Class number related Peter Gustav Lejeune Dirichlet discovered formulas that relate the class number h of quadratic number fields to the Jacobi symbol.
For example: : Or using a more efficient computation: : The article Jacobi symbol has more examples of Legendre symbol manipulation.
Generalizations of the symbol include the Jacobi symbol and Dirichlet characters of higher order.
Related functions * The Jacobi symbol is a generalization of the Legendre symbol that allows for a composite second (bottom) argument n, although n must still be odd and positive.
Then the Jacobi symbol satisfies the law of quadratic reciprocity : : Let λ(n) be Liouville's function.