and Applied Analysis 3 2. Auxiliary Results Here we quote some auxiliary results which will be used in the proofs of the main results. The first lemma can be proved in a standard way see, e.g., in 13, Proposition 3.11 or in 15, Lemma 3 . Lemma 2.1. Assume that m ∈ N0, n ∈ N, p, q > 0, γ > −1, φ is an analytic self-map of D and u ∈ H D . Then the operator D φ,u : Hp,q,γ → W n μ is compact if and only if D φ,u : Hp,q,γ → W n μ is bounded and for any bounded sequence fk k∈N in Hp,q,γ which converges to zero uniformly on compact subsets of D, D φ,ufk → 0 inW n μ as k → ∞. The next lemma is known, but we give a proof of it for the benefit of the reader. Lemma 2.2. Assume that n ∈ N0, 0 −1 and m > 1 β one has ∫1 0 1 − r β ( 1 − ρrm ≤ C ( 1 − ρ) β−m, 0 0 and Dn a ∣ ∣ ∣ ∣ ∣ ∣ ∣ ∣ ∣ ∣ ∣ ∣ ∣ ∣ 1 1 · · · 1 a a 1 · · · a n − 1 a a 1 a 1 a 2 · · · a n − 1 a n · · · n−2 ∏