The relative widths Kn(W2α(T), MW2β(T), L2(T)), T=[0, 2π], is studied and the smallest number M which makes the equality Kn(W2α(T), MW2β(T), L2(T))=dn(W2α(T), L2(T)) valid is obtained, and the asymptotic order of relative widths Kn(W2α(T), W2α(T), Lq(T) ) is obtained, where α≥β>0, 1≤q ≤ ∞ , Kn (., ., Lq(T)) and dn(., Lq(T)) denote respectively the relative widths and the widths in the sense of Kolmogorov in Lq(T), and MWpα(T), 1≤ p ≤ ∞ , denotes the collection of 2π-periodic and continuous functions f representable as a convolution f(t)=c+(Bα* g)(t), where Bα* g denotes the convolution of Bα and g, for g ∈ Lp(T) satisfying ∫02πg(τ)dτ=0 and ||g||p ≤ M. Here Bα is in L1(T) with the Fourier expansion
Bα(t) )=1/2π ∑' k∈ Z(ik)-αeikt, where ∑' means that the term is omitted when k=0.