“…Besides the new upper bounds obtained in [10], [11], the main ingredient for the proof of Theorem 1 is a factorisation recalled in Lemma 1 below. It easily follows from Lemma 1 and from Theorem NL that, in order to prove ( * ) Actually, it is explained in [17], page 476, and in [5], Théorème 15, that inserting results from [7] and [1] in the same proof yields that (1) has no solution (x, y, n, q) with ω(n) > q − 2 that (1) has no solution outside (S), it is sufficient to solve (2) for any odd prime numbers p and q. We are able to considerably improve this assertion.…”