Browsing by Author "Roldan Lopez de Hierro, Antonio Francisco"

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Citation - WoS: 8
Citation - Scopus: 12
Extended Proinov X-Contractions in Metric Spaces and Fuzzy Metric Spaces Satisfying the Property Nc by Avoiding the Monotone Condition
(Springer-verlag Italia Srl, 2022) Martinez-Moreno, Juan; Shahzad, Naseer; Roldan Lopez de Hierro, Antonio Francisco; Karapinar, Erdal; 19184; 02.02. Matematik; 02. Fen-Edebiyat Fakültesi; 01. Çankaya Üniversitesi
In recent years, Fixed Point Theory has achieved great importance within Nonlinear Analysis especially due to its interesting applications in real-world contexts. Its methodology is based on the comparison between the distances between two points and their respective images through a nonlinear operator. This comparison is made through contractive conditions involving auxiliary functions whose role is increasingly decisive, and which are acquiring a prominent role in Functional Analysis. Very recently, Proinov introduced new fixed point results that have very much attracted the researchers' attention especially due to the extraordinarily weak conditions on the auxiliary functions considered. However, one of them, the nondecreasing character of the main function, has been used for many years without the chance of being replaced by another alternative property. In this way, several researchers have recently raised this question as an open problem in this field of study. In order to face this open problem, in this work we introduce a novel class of auxiliary functions that serve to define contractions, both in metric spaces and in fuzzy metric spaces, which, in addition to generalizing to Proinov contractions, avoid the nondecreasing character of themain auxiliary function. Furthermore, we present these new results in the setting of fuzzy metric spaces that satisfy the conditionNC, which open new possibilities in the metric theory compared to classic non-Archimedean fuzzy metric spaces. Finally, we include some illustrative examples to show how to apply the novel theorems to cases that are not covered by other previous results.
Citation - WoS: 21
Citation - Scopus: 27
Extended Simulation Function Via Rational Expressions
(Mdpi, 2020) Alqahtani, Badr; Karapinar, Erdal; Roldan Lopez de Hierro, Antonio Francisco; Alsubaie, Rawan; 19184; 02.02. Matematik; 02. Fen-Edebiyat Fakültesi; 01. Çankaya Üniversitesi
In this paper, we introduce some common fixed point theorems for two distinct self-mappings in the setting of metric spaces by using the notion of a simulation function introduced in 2015. The contractivity conditions have not to be verified for all pairs of points of the space because it is endowed with an antecedent conditions. They are also of rational type because the involved terms in the contractivity upper bound are expressed, in some cases, as quotients.
Citation - WoS: 23
Citation - Scopus: 27
Proinov-Type Fixed-Point Results in Non-Archimedean Fuzzy Metric Spaces
(Mdpi, 2021) Fulga, Andreea; Karapinar, Erdal; Shahzad, Naseer; Roldan Lopez de Hierro, Antonio Francisco; 19184; 02.02. Matematik; 02. Fen-Edebiyat Fakültesi; 01. Çankaya Üniversitesi
Very recently, Proinov introduced a great family of contractions in the setting of complete metric spaces that has attracted the attention of many researchers because of the very weak conditions that are assumed on the involved functions. Inspired by Proinov's results, in this paper, we introduce a new class of contractions in the setting of fuzzy metric spaces (in the sense of George and Veeramani) that are able to translate to this framework the best advantages of the abovementioned auxiliary functions. Accordingly, we present some results about the existence and uniqueness of fixed points for this class of fuzzy contractions in the setting of non-Archimedean fuzzy metric spaces.