Tripled coincidence theorems for contractive type mappings in partially ordered metric spaces

In this paper we introduce the concept of a tripled coincidence point for a pair of nonlinear contractive mappings F : X3 → X and g : X → X. The obtained results extend recent coincidence theorems due to Ćirić and Lakshmikantham [V. Lakshmikantham, L. Ćirić, L., Coupled fixed point theorems for nonlinear contractions in partially ordered metric spaces, Nonlinear Anal. 70 (2009) 4341-4349].