Existence of solution for biharmonic systems with indefinite weights

In this article we deal with the existence questions to the nonlinear biharmonic systems. Using theory of monotone operators, we show the existence of a unique weak solution to the weighted biharmonic systems. We also show the existence of a positive solution to weighted biharmonic systems in the unit ball in Rn, using Leray Schauder fixed point theorem. In this

study we allow sign-changing weights.