Monotone iterative technique for a coupled system of nonlinear Hadamard fractional differential equations

In this paper, we investigate the extremal solutions for a coupled system of nonlinear Hadamard fractional differential equations with Cauchy initial value conditions. By using the comparison principle and the monotone iterative technique combined with the method of upper and lower solutions, we obtain the existence and iterative methods of extremal solution to the system. Finally, an example with numerical simulation is given to show the effectiveness of our main results.