Marwa, Bouguerra2019-07-142019-07-142019http://dspace.univ-msila.dz:8080//xmlui/handle/123456789/14983The aim of this memory is to study the existence and uniqueness of boundary value problem for nonlinear q-symmetric fractional differential equations. Based upon a contraction mapping principle, Schauder's and nonlinear alternative Leray-Schauder's fixed point theorems. We obtain various results of the existence and uniqueness about the given problem. Several examples are presented to illustrate the usefulness of our results.enq-symmetric differential equation- fixed point theorem- existence- uniquenessThesis