Recently N. C. Ankeny derived
a law of r-th power reciprocity, where !r is an odd prime: q is an r-th power residue,
modulo p ≡ 1(modr), if and only if the r-th power of the Gaussian sum (or
Lagrange resolvent) τ(χ), which depends upon p and r, is an r-th power in GF(qf),
where q belongs to the exponent f(modr). τ(χ)r can be written as the product of
algebraic integers known as Jacobi sums. Conditions in which the reciprocity
criterion can be expressed in terms of a single Jacobi sum are presented in this
paper.