5 papers
On discrete and semimetric fixed point theorems for nonexpansive mappings
A. El Adraoui, M. Kabil, A. Kamous +1
This work is a comparative study between the existence of fixed point for homomorphisms in a class of binary relationnal systems and the existence of fixed point for nonexpansive m…
Bipartite graphs and best proximity pairs
Karim Chaira, Oleksiy Dovgoshey, Samih Lazaiz
We say that a bipartite graph with fixed parts , is proximinal if there is a semimetric space such that and are disjoint proximinal subsets of …
Best proximity pairs in ultrametric spaces
K. Chaira, O. Dovgoshey, S. Lazaiz
In the present paper, we study the existence of best proximity pairs in ultrametric spaces. We show, under suitable assumptions, that the proximinal pair has a best proximi…
Best proximity points in ultrametric spaces
Karim Chaira, Samih Lazaiz
In the present paper, we study the existence of best proximity pair in ultrametric spaces. We show, under suitable assumptions, that the proximinal pair has a best proximit…
On Caristi fixed point theorem for set-valued mappings
Karim Chaira, Soumia Chaira, Samih Lazaiz
The aim of this paper is to discuss Penot's problem on a generalization of Caristi's fixed point theorem. We settle this problem in the negative and we present some new theorems on…