Oscillation of difference systems of the neutral type

The authors consider the nonlinear difference systems @D(x"n-a"nx"@s"("n"))=p"ng(y"n)@Dy"n=@dq"nf(x"@t"("n")),n@?N(n"0) where @d=+/-1,{a"n},{p"n} and {q"n} are real sequences, {@s(n)} and {@t(n)} are real non-negative sequences of integers, and f,g:R->R are continuous with uf(u)>0 and ug(u)>0 for u 0. The authors obtain sufficient conditions for all solutions of the system to be oscillatory. Examples to illustrate the results are included.