[EN] We obtain a characterization of Hausdorff left K-complete quasi-metric spaces by means of alpha-psi-contractive mappings, from which we deduce the somewhat surprising fact that one the main fixed point theorems of Samet, Vetro, and Vetro (see "Fixed point theorems for alpha-psi-contractive type mappings", Nonlinear Anal. 2012, 75, 2154-2165), characterizes the metric completeness.
This research was partially funded by Ministerio de Ciencia, Innovacion y Universidades, under grant PGC2018-095709-B-C21 and AEI/FEDER, UE funds.