A basic theorem in elementary number theory which asserts that for a prime p and integer a with p not dividing a, one has a^{p-1} ≡ 1 (mod p); equivalently a^p ≡ a (mod p) for all integers a.
A number-theoretic statement that if p is prime and a is an integer not divisible by p, then a^{p−1} ≡ 1 (mod p); equivalently a^p ≡ a (mod p) for all integers a.