International Journal of Mathematics and Mathematical Sciences
Volume 31 (2002), Issue 7, Pages 443-447
doi:10.1155/S0161171202110404
Abstract
We prove a new minimization theorem in quasi-metric spaces, which improves the results of Takahashi (1993). Further, this theorem
is used to generalize Caristi's fixed point theorem and Ekeland's
ϵ-variational principle.