Probable Prime
In number theory, a probable prime (PRP) is an integer that satisfies a specific condition also satisfied by all prime numbers. Different types of probable primes have different specific conditions. While there may be probable primes that are composite (called pseudoprimes), the condition is generally chosen in order to make such exceptions rare.
Fermat's test for compositeness, which is based on Fermat's little theorem, works as follows: given an integer n, choose some integer a coprime to n and calculate an − 1 modulo n. If the result is different from 1, n is composite. If it is 1, n may or may not be prime; n is then called a (weak) probable prime to base a.
Read more about Probable Prime: Properties, Variations
Famous quotes containing the words probable and/or prime:
“I hope I may claim in the present work to have made it probable that the laws of arithmetic are analytic judgments and consequently a priori. Arithmetic thus becomes simply a development of logic, and every proposition of arithmetic a law of logic, albeit a derivative one. To apply arithmetic in the physical sciences is to bring logic to bear on observed facts; calculation becomes deduction.”
—Gottlob Frege (1848–1925)
“If Montaigne is a man in the prime of life sitting in his study on a warm morning and putting down the sum of his experience in his rich, sinewy prose, then Pascal is that same man lying awake in the small hours of the night when death seems very close and every thought is heightened by the apprehension that it may be his last.”
—Cyril Connolly (1903–1974)