Interaction between coefficient conditions and solution conditions of differential equations in the unit disk

Abstract

The influence of the normality of the coefficient A(z) of the differential equation f(k)+A(z)f=0 on a solution f and also the influence of the normality of a solution f on A(z) are investigated in the unit disk. In particular, an estimate of P. Lappan is used to determine restrictions on the growth of a meromorphic function A(z) when a solution f is α-normal.