## Disconjugacy, disfocality, and oscillation of second order difference equations.(English)Zbl 0791.39001

There are given necessary and sufficient conditions for the disconjugacy, disfocality and oscillation, respectively, of the equation $$\Delta (r_ n \Delta x_ n)+p_ nx_{n+1}=0$$ for $$n=0,1,2,\dots$$, real $$p_ n$$ and $$r_ n>0$$. The conditions are given explicitly in terms of the coefficients in the equation.
Reviewer: L.Berg (Rostock)