Suppose that w is analytic in the open unit disc Δ in the z-plane. The Schwarzian derivative of w is defined by(for basic properties of {w, z} we refer to Hille ((3), p. 375)). Let denote the class of functions w which are analytic in Δ and satisfy the conditions
In what follows, we suppose that ƒ(z) = Σ0∞anzn is regular for |z| < 1. LetandThen (see, for example, [6, pp. 235-236]), for 0 ≦ r < ρ < 1, we have:The following results are well known.
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