Sturmian comparison method in oscillation study for discrete difference equations. I
The author presents a method for studying the oscillatory properties of discrete difference equations and inequalities of advance and mixed-type delays, by obtaining Sturmian-type comparison theorems which allow the possibility of estimating, from above and from below, the intervals on which the solution does not change sign. The open problem 8.6 of \textit{G. Ladas} [Int. Conf. Differential Equations, Colorado Springs, USA (1989)] is completely solved.
scientific article; zbMATH DE number 527366