Ford's Theorem
Ford (1999) proved that for every integer k ≥ 2 there is a number m for which the equation φ(x) = m has exactly k solutions; this result had previously been conjectured by Wacław Sierpiński. However, no such m is known for k = 1. Carmichael's totient function conjecture is the statement that there is no such m.
Read more about this topic: Euler's Totient Function
Famous quotes containing the words ford and/or theorem:
“Even the strongest man needs friends.”
—Mario Puzo, U.S. author, screenwriter, and Francis Ford Coppola, U.S. director, screenwriter. Don Lucase, The Godfather III, advice given to Vincent (Andy Garcia)
“To insure the adoration of a theorem for any length of time, faith is not enough, a police force is needed as well.”
—Albert Camus (1913–1960)