Fermat's little theorem

Etymology
, who stated a version of the theorem in a letter in 1640. Called little to distinguish it from Fermat's Last Theorem.

Proper noun

 * 1)  The theorem that, for any prime number $$p$$ and integer $$a$$, $$a^p - a$$ is an integer multiple of $$p$$.
 * 2) * 1999, John Stillwell, Translator's introduction,, (supplements), Lectures on Number Theory, [1863, P. G. Lejeune Dirichlet, R. Dedekind, ], , page xi,
 * When combined with the historical remarks made by Gauss himself, they give a bird's eye view of number theory from approximately 1640 to 1840 - from Fermat's little theorem to L-functions - the period which produced the problems and ideas which are still at the center of the subject.
 * 1) * 1999, Siguna Müller, On the Combined Fermat/Lucas Probable Prime Test, Michael Walker (editor), Cryptography and Coding: 7th IMA International Conference, Springer, 1746, page 222,
 * Most of the pseudoprimality tests originate in some sense on Fermat's Little Theorem an−1 ≡ 1 mod n.

Translations

 * French: petit théorème de Fermat
 * Hungarian:
 * Italian: piccolo teorema di Fermat
 * Russian: малая теорема Ферма