The second derivative of a meromorphic function (Q2758142)

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scientific article; zbMATH DE number 1679456
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The second derivative of a meromorphic function
scientific article; zbMATH DE number 1679456

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    6 December 2001
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    zeros of derivatives
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    meromorphic function
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    The second derivative of a meromorphic function (English)
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    Let \(f\) be a meromorphic function of finite order in the plane and \(k\varepsilon\mathbb{N}\), \(k\geq 2\). Six years ago the author conjectured, that \(f\) has finitely many poles if \(f^{(k)}\) has finitely many zeros only. In the paper under review the author shows that the conjecture is true if either (i) \(f\) has order less than \(1+\varepsilon\) for some positive absolute constant \(\varepsilon\), or (ii) \(f^{(m)}\), for some \(0\leq m<k\), has few zeros away from the real axis. More than that he also gives an estimate for the frequency of distinct poles of \(f\). Remark: Meanwhile the author showed that the conjecture is true without any additional condition.
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