Let A be a commutative Noetherian ring of characteristic p>0, such that
dim(A)=d. Let P be a projective A[T1β,...,Tnβ]-module of rank d. We
show that P is cancellative if and only if P/P is
cancellative. We deduce some applications. In one of the interesting
consequences, we show that the Bass-Quillen conjecture has an affirmative
answer in dimension three, when 2 is invertible.Comment: The proof of 2.2 is not correc