On second order linear differential polynomials
Let \(f\) be meromorphic in \(G:= \{z\in \mathbb{C}\mid R\leq | z|< \infty\}\) and define \(F\) by \[ F:= f''+ a_ 1 f' a_ 0 f, \] where \(a_ 0\) and \(a_ 1\) are rational at infinity. The author classifies all meromorphic functions \(f\) such that \(f\cdot F\) has no zeros in \(G\). For the details we have to refer to the paper.
inhomogeneous linear differential equations
scientific article; zbMATH DE number 687810
scientific article