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Outline

Hardy spaces of close-to-convex functions and their derivatives

1978, Transactions of the American Mathematical …

Abstract

Let f{z) = J,fanz" be close-to-convex on the unit disc. It is shown that (a) if A > 0, then/ belongs to the Hardy space Hx if and only if 2 «x"2|a"|x is finite and that (b) if 0 < X < 1, then/' G Hx if and only if either 2 na_2|ajx or, equivalently, fl0Mx(r,f')dr is convergent. It is noted that the first of these results does not extend to the full class of univalent functions and that the second is best possible in a number of different senses.

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