We develop criteria for the nonexistence of eventually positive (negative) and nondecreasing (nonincreasing) solutions of the partial difference equation del(m) del(n)y(m, n) + P (m, n, y (m + k, n + l)) = Q(m, n, y(m + k, n + l)) and [GRAPHICS] Several examples which dwell upon the importance of our results are also included. (C) 1997 Academic Press. [References: 33]
展开▼
