- - - Fundamental and Numerical Mathematics Laboratory, Department of Mathematics, Faculty of Science, Ferhat Abbas University, Setif, Algeria
- - - Fundamental and Numerical Mathematics Laboratory, Department of Mathematics, Faculty of Science, Ferhat Abbas University, Setif, Algeria
- - - Fundamental and Numerical Mathematics Laboratory, Department of Mathematics, Faculty of Science, Ferhat Abbas University, Setif, Algeria

In this paper, we prove the existence of weak global solutions for a class of generic reaction diffusion systems for which two main properties hold: the quasi-positivity and a triangular structure condition on the nonlinearities. The main result is a generalization of the work already done on models of a single reaction-diffusion equation. The model studied is applied in image recovery and contrast enhancement. It can also be applied to many models in biology and radiology.

reaction diffusion system, global existence, Schauder fixed point theorem