In this article we estimate the sum of coefficients for functions with restrictions on the pre-Schwarzian derivative. We obtain an estimate, which is sharp up to a constant and find upper and lower bounds for that constant. Also we estimate the sum of the first three coefficients for all functions f, such that \(\log f'(z)\) is bounded with respect to the Bloch norm.

中文翻译：

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一元函数系数的Landau型估计

在本文中，我们估计了受前Schwarzian导数限制的函数的系数总和。我们获得一个估计，该估计可以精确到一个常数，并找到该常数的上限和下限。我们还估计所有函数f的前三个系数的总和，从而\（\ log f'（z）\）相对于Bloch范数有界。