摘要：This paper is devoted to derivation of some necessary and sufficient conditions for the existence of positive solutions to a singular second-order system of dynamic equations with Dirichlet boundary conditions. The results are obtained by employing fixed-point theorems and the method of lower and upper solutions. MSC:34B16, 34K10, 39A13.
关键词：time scales ; boundary value problem in dynamic equations ; upper and lower solutions
