Sur la norme de Fourier. III.
Let [0;a₁(x),a₂(x),…] be the regular continued fraction expansion of an irrational x ∈ [0,1]. We prove mainly that, for α > 0, β ≥ 0 and for almost all x ∈ [0,1], if α < 1 and β ≥ 0, if α = 1 and β < 1, and, if α > 1 or α = 1 and β >1, , , where if and otherwise, for all i ∈ 1,…,n.