Applications of ball spaces theory: fixed point theorems in semimetric spaces and ball convergence

Fuente: arXiv
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Main Authors: Nowakowski, Piotr, Turoboś, Filip
Format: Preprint
Published: 2021
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author Nowakowski, Piotr
Turoboś, Filip
author_facet Nowakowski, Piotr
Turoboś, Filip
contents In the paper we apply some of the results from the theory of ball spaces in the semimetric spaces. This allowed us to obtain some fixed point theorems which we believe to be unknown to this day. We also show the limitations of the ball space approach to this topic. As a byproduct, we obtain the equivalence of some different notions of completness in semimetric spaces where the distance function is $1$-continuous. In the second part of the article, we generalize Caristi-Kirk results for for $b$-metric spaces. Additionally, we obtain characterization of semicompleteness for $1$-continuous $b$-metric space via fixed point theorem analogous to the result of Suzuki. In the epilogue, we introduce the concept of convergence in ball spaces, based on the idea that balls should resemble closed sets in topological sets. We prove several of its properties, compare it with convergence in semimetric spaces and pose several open questions connected with this notion.
format Preprint
id arxiv_https___arxiv_org_abs_2110_00848
institution arXiv
publishDate 2021
record_format arxiv
spellingShingle Applications of ball spaces theory: fixed point theorems in semimetric spaces and ball convergence
Nowakowski, Piotr
Turoboś, Filip
General Topology
54E25, 47H10, 54A05
In the paper we apply some of the results from the theory of ball spaces in the semimetric spaces. This allowed us to obtain some fixed point theorems which we believe to be unknown to this day. We also show the limitations of the ball space approach to this topic. As a byproduct, we obtain the equivalence of some different notions of completness in semimetric spaces where the distance function is $1$-continuous. In the second part of the article, we generalize Caristi-Kirk results for for $b$-metric spaces. Additionally, we obtain characterization of semicompleteness for $1$-continuous $b$-metric space via fixed point theorem analogous to the result of Suzuki. In the epilogue, we introduce the concept of convergence in ball spaces, based on the idea that balls should resemble closed sets in topological sets. We prove several of its properties, compare it with convergence in semimetric spaces and pose several open questions connected with this notion.
title Applications of ball spaces theory: fixed point theorems in semimetric spaces and ball convergence
topic General Topology
54E25, 47H10, 54A05
url https://arxiv.org/abs/2110.00848