用分歧理论考察二阶离散边值问题{-Δ[p(k-1)Δu(k-1)]+q(k)u(k)=λa(k)f(u(k)),k∈[1,N]_Z,g_1(λ,u(0),Δu(0))=0,g_2(λ,u(N+1),Δu(N))=0正解的全局结构,得到了该问题正解存在的最优充分条件.其中:λ〉0是参数;[1,N]Z={1,2,…,N};p:[0,N+1]Z→+,q,a:[1,N]Z→R^+且对k∈[1,N]Z,a(k)〉0;g_1∈C(R^+×R^+×R^+,R^+);g_2∈C(R^+×R^+×(-∞,0],R^+);f∈C(R^+,R^^+).
By using bifurcation theory,the author investigated the global structure of positive solutions for the following second-order nonlinear discrete boundary value problem {-Δ[p(k-1)Δu(k-1)]+q(k)u(k)=λa(k)f(u(k)), k∈[1,N]_Z,g_1(λ,u(0),Δu(0))=0, g_2(λ,u(N +1),Δu(N))=0{,and obtained the optimal sufficient conditions for the existence of the positive solution of the problem.whereλ〉0is parameter,[1,N]_Z= {1,2,…N},p:[0,N +1]Z → R^+,q,a:[1,N]Z → R+and a(k)〉0,k∈[1,N]Z,g_1∈C(R^+×R^+×R^+,R^+);g_2∈C(R^+×R^+×(-∞,0],R^+);f∈C(R^+,R^+).