Interval oscillation criteria for second order neutral nonlinear differential equations

摘要

Some oscillation criteria for the second order neutral nonlinear differential equation[y(t)+p(t)y(σ(t))]″+∑i=1nqi(t)fi(y(τi(t)))=0,t⩾t0are established. New oscillation criteria are different from most known ones in the sense that they are based on the information only on a sequence of subintervals of [t0,∞), rather than on the whole half-line. Our results are more natural according to the Sturm Separation Theorem.