Abstract
In this article, we study a system of Hilfer (k,psi)-fractional differential equations, subject to nonlocal boundary conditions involving Hilfer (k,psi)-derivatives and (k,psi)-integrals. The results for the mentioned system are established by using Monch's fixed point theorem, then the Ulam-Hyers technique is used to verify the stability of the solution for the proposed system. In general, symmetry and fractional differential equations are related to each other. When a generalized Hilfer fractional derivative is modified, asymmetric results are obtained. This study concludes with an applied example illustrating the existence results obtained by Monch's theorem.