摘要：Let $T > 1$ be an integer, and let $\mathbb{T}=\{1, 2,\ldots ,T\}$. We show the existence of positive solutions of the Dirichlet boundary value problem with second-order difference operator$$ \textstyle\begin{cases} -\triangle ^{2} u(j-1)=\lambda f(j, u(j)), \quad j\in \mathbb{T},\\ u(0)=u(T + 1)=0, \end{cases} $$ where $\lambda >0$ is a parameter, and $f:\mathbb{T}\times \mathbb{R} ^{+}\to \mathbb{R}$ is a continuous function satisfying $f(j, 0)<0$ for all $j\in \mathbb{T}$. The proofs of the main results are based upon topological degree and global bifurcation techniques.
