1. A fixed point theorem for non-negative functions.
- Author
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Aydi, Hassen, Samet, Bessem, and Sen, Manuel De la
- Abstract
In this paper, we are concerned with the study of the existence and uniqueness of fixed points for the class of functions f : C → C satisfying the inequality ℓ (α f (t) + (1 − α) f (s)) ≤ σ ℓ (α t + (1 − α) s) for every t , s ∈ C with f (t) ≠ f (s) , where C is a closed subset of [ 0 , ∞) , α , σ ∈ (0 , 1) are constants, and ℓ : [ 0 , ∞) → [ 0 , ∞) is a function satisfying the condition inf t > 0 ℓ (t) t ρ > 0 for some constant ρ > 0. Namely, under a weak continuity condition imposed on f , we show that f possesses a unique fixed point, and for every t 0 ∈ C , the Picard sequence defined by t n + 1 = f (t n) , n ≥ 0 , converges to this fixed point. Next, we study the special cases when C is a closed interval and ℓ is a convex or concave function. Namely, making use of the Hermite-Hadamard inequalities, we obtain several new fixed point theorems. To the best of our knowledge, the considered class of functions was never previously investigated in the literature. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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