This is actually Fermat's Last Theorem: Pierre de Fermat said he had a proof that there were no integer values of a,b and c, if n was greater than 2. He wrote in the margin of a book called 'Arithmetica" that: "I have discovered a truly marvelous demonstration of this proposition that this margin is too narrow to contain." Which is similar to what Friday said in this chapter. It is commonly thought that Fermat did not have a proof, as one was never found. This theorem was eventually proved over 350 years later by Professor Andrew Wiles.