Common Fixed Point Theorems Of Weakly Compatible Maps Satisfying (f,g)-Weakly Contractive Condition And Invariant Approximation Results
Babu G. V. R., Ratna Babu D, Alemayehu Negash
TL;DR
The paper introduces $(f,g)$-weakly contractive mappings for three selfmaps on a metric space and proves existence and uniqueness of a common fixed point for $T,f,g$ under weak compatibility and invariance conditions, with $\\overline{T(X)}$ embedded in both $f(X)$ and $g(X)$ and forming a complete subspace. It further proves the convergence of the modified Mann and modified Ishikawa iterations to this unique fixed point in normed spaces under appropriate summability of parameters. Additionally, invariant-approximation results show that the common fixed point can be characterized as a best approximation from invariant compact subsets. Together, these results extend and unify prior fixed-point theorems by Beg–Abbas and Azam–Shakeel, and point to broader applicability in nonlinear analysis and equations.
Abstract
We prove the existence of common fixed points for three selfmaps $T,f$ and $g$ defined on a metric space $(X,d)$ satisfying, $T$ is $(f,g)$-weakly contractive; and the pairs $(T,f)$ and $(T,g)$ are weakly compatible. Also, for such $T,f$ and $g$, we prove the convergence of modified Mann iteration and modified Ishikawa iteration with respect to $T,f$ and $g$ to their common fixed point, in a normed space. Further, we obtain invariant approximation results from the set of best approximations to common fixed points of $T,f$ and $g$.
