OSCILLATION OF FOURTH-ORDER DELAY DIFFERENTIAL EQUATIONS

摘要

This article deals with the oscillation of a certain class of fourth-order delay differential equations. Some new oscillation criteria (including Hille- and Nehari-type criteria) are presented. The results obtained in the paper improve some results from [C. Zhang, T. Li, B. Sun, and E. Thandapani, Appl. Math. Lett., 24, 1618 (2011)]. Two examples are presented to illustrate our main results.