Oscillation of nonlinear delay difference equations (Q5917456)

The authors obtain new oscillation criteria for all solutions of the nonlinear delay difference equation \[ x_{n+1} - x_n + p_n f(x_{n-k}) = 0, \quad n = 0, 1,\dots , \] where \(\{ p_n \}\) is a sequence of nonnegative numbers, \(k\) is a positive integer, and continuous function \(f\) satisfies inequality \(uf(u) > 0 \) for \(n \not= 0\).