Positive solutions of a weakly singular periodic eco- economic system with changing-sign perturbation

In this paper, we establish the positive bounded solutions for a changing-sign periodic perturbed differential system with weak singularity in eco-economic and other applied fields. The conditions for the existence of solution are established for the positive, negative and semipositone cases of nonlinear term, and the perturbation is allowed to be a singular and changing-sign L^1(0, T) function.