We prove versions of Ekeland, Takahashi and Caristi principles in pre-ordered quasi-metric
spaces, the equivalence between these principles, as well as their equivalence to some …

The famous Banach contraction principle holds in complete metric spaces, but
completeness is not a necessary condition: there are incomplete metric spaces on which …

In this paper, driven by Behavioral applications to human dynamics, we consider the
characterization of completeness in pseudo-quasimetric spaces in term of a generalization …

Using a pre-order principle in [Qiu JH. A pre-order principle and set-valued Ekeland
variational principle. J Math Anal Appl. 2014; 419: 904–937], we establish a general …

We prove versions of Ekeland, Takahashi and Caristi principles in sequentially right K-
complete quasi-pseudometric spaces (meaning asymmetric pseudometric spaces), the …

This paper addresses a large class of vector optimization problems in infinite-dimensional
spaces with respect to two important binary relations derived from domination structures …

This paper is devoted to new versions of Ekeland's variational principle in set optimization
with domination structure, where set optimization is an extension of vector optimization from …

By using a pre-order principle in [Qiu JH. A pre-order principle and set-valued Ekeland
variational principle. J Math Anal Appl. 2014; 419: 904–937], we establish a general …

In this paper, we generalize Ekeland's variational principle in the new context of cone
pseudo-quasimetric spaces. We propose this extension for applications to group dynamics …

Roughly speaking, Ekeland's Variational Principle (EkVP)(J. Math. Anal. Appl. 47 (1974),
324–353) asserts the existence of strict minima of some perturbed versions of lower …