Interval Criteria for Oscillation of Second-Order Linear Ordinary Differential Equations

New oscillation criteria are established for the equation pyX .Xqqys0 that are different from most known ones in the sense that they are based on the information only on a sequence of subintervals of wt0 , `., rather than on the whole half-line. Our results are more natural according to the Sturm Separation Theorem and sharper than some previous results, and can be applied to extreme cases such as Ht`0q t. dtsy`.