“…Suppose that f ∈ (L q , l p ) α (R d ) and there exists a constant C > 0 such that [2]. Also, many useful results in Fourier analysis, wellknown in the Lebesgue spaces, have been extended in the setting of the spaces (L q , l p ) α (R d ) and W 1 (L q , l p ) α (R d ) (see for instance [1], [6], [7], [9], [14], [15], [17] and [18]).…”