“…The sets B(s, k, n, j) have been proven to be open in [20] for q (n) j ≥ 1 and in [29] for q (n) j = 0. We will now prove that each A(i, s, m, n, j) is an open set in H(Ω) for q (n) j ≥ 1 (see also [24]). We fix the parameters i, s, m, n ≥ 1 and j ∈ {1, • • • , N (n)} and we consider a function f ∈ A(i, s, m, n, j).…”