title: Existence and Uniqueness of Positive Solution for Discrete Multipoint Boundary Value Problems.
abstract: It is expected in this paper to investigate the existence and uniqueness of positive solution for the following difference equation: -Δ(2) u(t - 1) = f(t, u(t)) + g(t, u(t)), t ∈ ℤ 1,  T , subject to boundary conditions either u(0) - βΔu(0) = 0, u(T + 1) = αu(η) or Δu(0) = 0, u(T + 1) = αu(η), where 0 < α < 1, β > 0,  and η ∈ ℤ 2,T-1. The proof of the main result is based upon a fixed point theorem of a sum operator. It is expected in this paper not only to establish existence and uniqueness of positive solution, but also to show a way to construct a series to approximate it by iteration.
authors.affiliation: Department of Mathematics, Northwest Normal University, Lanzhou 730070, China.
authors.forename: Huili
authors.initials: H
authors.lastname: Ma
authors.affiliation: Department of Mathematics, Northwest Normal University, Lanzhou 730070, China.
authors.forename: Huifang
authors.initials: H
authors.lastname: Ma