关于线性微分多项式的Hayman-Yang不等式(英文)

Hayman-Yang's inequality for linear differential polynomials

下述问题得到彻底解决:在著名的Hayman-Yang不等式中,k阶导数f(k)能否被替换成一般的k阶线性微分多项式a0f+a1f +…+akf(k)?一个例子表明本文中的结果是最基本的,定理的条件不能减弱.

The following question obtains a complete answer:Can the kthorder derivative f(k) apperaing in wellknown HaymanYangs inequality be replaced by a general linear kthorder differential polynomial  a0f+a1f+...+akf(k)? An example shows the result in the present paper is essential.