The existence results for a coupled system of nonlinear fractional differential equations with multi-point boundary conditions

In this paper, we study a coupled system of nonlinear fractional differential equations with multi-point boundary condi- tions. The differential operator is taken in the Riemann-Liouville sense. Applying the Schauder fixed-point theorem and the contrac- tion mapping principle, two existence results are obtained for the following system D^{alpha}_{0+}x(t)=fleft(t,y(t),D^{p}_{0+}y(t)right), t in (0,1), D^{beta}_{0+}y(t)=gleft(t,x(t),D^{q}_{0+}x(t)right), t in (0,1), x(0)=x'(0)=x''(0)=cdots=x^{(m-2)}(0)=0, x(1)=lambda x(xi), 0y(0)=y',(0)=y''(0 =cdots=y^{(m-2)},(0)=0, y(1)=lambda y(xi), 0where m in mathbb{N}, m geq, alpha,,beta in (m-1,m) and alpha,beta,p,q,lambda satisfy certain conditions.