Coincidence point theorems for G-isotone mappings in partially ordered metric spaces

Abstract

We establish coincidence and common fixed-point theorems for G-isotone mappings in partially ordered metric spaces, which include the corresponding coupled, tripled and quadruple fixed-point theorems as special cases. Our proofs are simpler and essentially different from the ones devoted to coupled, tripled and quadruple fixed-point problems that appeared in the last years. © 2013 Wang; licensee Springer.