Chebotarev Density Theorem

A theorem in algebraic number theory that identifies the natural density of rational primes whose Frobenius conjugacy class in the Galois group of a finite Galois extension lies in a prescribed conjugacy class; the density equals the size of that conjugacy class divided by the order of the Galois group.

A theorem that describes the asymptotic density of prime ideals in a number field whose Frobenius conjugacy class lies in a specified conjugacy class C of the Galois group of a finite Galois extension: the (natural) density equals |C|/|G|.