Fixed point results and the Ekeland variational principle in vector $B$-metric spaces
Radu Precup, Andrei Stan
TL;DR
This work introduces vector $B$-metric spaces as a matrix-generalization of $b$-metric spaces, where $d:X\times X\to\mathbb{R}^n_+$ and $d(u,w)\leq B(d(u,v)+d(v,w))$. It develops a comprehensive fixed-point theory in this setting, including Perov-type contractions, error estimates, and stability results, as well as an Avramescu-type theorem for two-mapping systems. The paper also extends Ekeland's variational principle and Caristi's fixed point theorem to vector $B$-metric spaces, and derives corresponding $b$-metric variants, thereby providing a broad variational-analytic framework for vector-valued distances. These results generalize and unify many known scalar $b$-metric results and open the door to new applications in nonlinear analysis and optimization with vector-valued metrics.
Abstract
In this paper, we extend the concept of \( b \)-metric spaces to the vectorial case, where the distance is vector-valued, and the constant in the triangle inequality axiom is replaced by a matrix. For such spaces, we establish results analogous to those in the \( b \)-metric setting: fixed-point theorems, stability results, and a variant of Ekeland's variational principle. As a consequence, we also derive a variant of Caristi's fixed-point theorem
