The aim of this paper is to establish some metrical coincidence and common fixed point theorems with an arbitrary relation under an implicit contractive condition which is general enough to cover a multitude of well known contraction conditions in one go besides yielding several new ones. We also provide an example to demonstrate the generality of our results over several well known corresponding results of the existing literature. Finally, we utilize our results to prove an existence theorem for ensuring the solution of an integral equation.
Definition 2.4. [27]A binary relation R defined on a non-empty set X is called complete if every pair of elements of X are comparable under that relation i.e., for all x, y in X, either (x, y) ∈ R or (y, x) ∈ R which is denoted by [x, y] ∈ R.
Proposition 2.1. [4] Let R be a binary relation defined on a non-empty set X. ThenDefinition 2.6.[5] Let T and g be two self-mappings defined on a non-empty set X. Then a binary relation R on X isNotice that on setting g = I, the identity mapping on X, Definition 2.6 reduces to Definition 2.5.Definition 2.7.[4] Let R be a binary relation defined on a non-empty set X. Then a sequence {x n } ⊂ X is said to be R-preserving if (x n , x n+1 ) ∈ R, ∀ n ∈ N 0 .Definition 2.8.[5] Let (X, d) be a metric space equipped with a binary relation R. Then (X, d) is said to be R-complete if every R-preserving Cauchy sequence in X converges to a point in X. 4 Remark 2.1. [5] Every complete metric space is R-complete, where R denotes a binary relation. Particularly, if R is universal relation, then notions of completeness and R-completeness coincide. Definition 2.9. [5] Let (X, d) be a metric space equipped with a binary relation R. Then a self-mapping T on X is said to be R-continuous at x if T x n d −→ T x whenever x n d −→ x, for any R-preserving sequence {x n } ⊂ X. Moreover, T is said to be R-continuous if it is R-continuous at every point of X. Definition 2.10. [5] Let (X, d) be a metric space equipped with a binary relation R and g a self-mapping on X. Then a self-mapping T on X is said to be (g, R)-continuous at x if T x n d −→ T x, for any R-preserving sequence {x n } ⊂ X with gx n d −→ gx. Moreover, T is called (g, R)-continuous if it is (g, R)-continuous at every point of X.Notice that on setting g = I, the identity mapping on X, Definition 2.10 reduces to Definition 2.9.Remark 2.2. Every continuous mapping is R-continuous, where R denotes a binary relation. Particularly, if R is universal relation, then notions of R-continuity and continuity coincide.Definition 2.11. [4] Let (X, d) be a metric space. Then a binary relation R on X is said to be d-self-closed if for any