On coupled coincidence point theorems on partially ordered G-metric spaces without mixed g-monotone

In this work, we prove the existence of a coupled coincidence point theorem of nonlinear contraction mappings in G-metric spaces without the mixed g-monotone property and give some examples of a nonlinear contraction mapping, which is not applied to the existence of coupled coincidence point by using the mixed monotone property. We also show the uniqueness of a coupled coincidence point of the given mapping. Further, we apply our results to the existence and uniqueness of a coupled coincidence point of the given mapping in partially ordered G-metric spaces.