Ax-Kochen theorem

Etymology
Named after James Ax and Simon B. Kochen.

Proper noun

 * 1)  A theorem stating that for each positive integer d there is a finite set Yd of prime numbers, such that if p is any prime not in Yd then every homogeneous polynomial of degree d over the p-adic numbers in at least d2+1 variables has a nontrivial zero.