THE HYPER ORDER OF SOLUTIONS OF SECOND ORDER DIFFERENTIAL EQUATIONS AND SUBNORMAL SOLUTIONS OF PERIODIC EQUATIONS

Abstract

In this paper, we obtain a precise estimation of the hyper order of solutions for a class of second order linear differential equations, and investigate the condition of the existence of nontrivial subnormal solution for a class of second order periodic equations. These results generalize the results of Gundersen, Steinbart [5] and Wittich [10]. Our methods of proofs are different from the methods applied in [5, 10].