逼近转化论和泛系逼近论(Ⅳ)

Theorem 1 If 1≤p≤∞, f∈W_p~(l)(D), then ω_k(δ,f,W_p~(l)(D))≤c(‖f‖_(l)_p),if f∈C~〔k+l〕(D), then ω_k(δ, f,W_p~(l)(D))≤c(δ~kmax‖(D)~(k)f‖_(()p)), where c is independent of δ≥0 and f. Theorem 2 If f∈W_p~(r)H_M~(a)(〔a,b〕)is of period b-a<∞, then ‖f‖_((s)t)≤cM~d‖f‖_((u)υ)~e, where d=δ/θ, e=(θ-δ)/θ, p≥1, t≥υ≥1, r>s≥u, δ=s-u+