Generalized Ekeland's Variational Principle on Generalized Metric Space.

In this paper, we present an Ekeland type variational principle, Takahashi type minimization theorem, Caristi type fixed point theorem and a generalized Oettli-Thera's equivalent form on complete D-metric space. We also prove that they are equivalent. The results present in this paper unify, improve and extend many known results due to Zhong, Ekeland, Takahashi, Caristi, and others. [ABSTRACT FROM AUTHOR]