“…Let a be a proper ideal of A. Following [1], a set of elements a 1 ,...,a n of A is called a-independent if every form feA[Xi,...,X n ] vanishing at a lt ..., a n has all its coefficients in a. It is well known (see, for example, [1; 3]) that if Xj,..., x n is an A-sequence in A, then x l ,...,…”