Tripled Coincidence Point Theorems with M-Invariant Set for a α-ψ-Contractive Mapping in Partially Metric Spaces

Abstract

In this paper, we introduce the notion M-invariant set for mapping
α : X3 × X3 → [0, +∞). We show the existence of a tripled coincidence point
theorem for a α-ψ-contractive mapping in partially ordered complete metric spaces
without the mixed g-monotone property, using the concept of M-invariant set. We
also show the uniqueness of a tripled common fixed point for such mappings and
give some examples to show the validity of our result.