Fuzzy quasi-pseudometrics on algebraic structures

Abstract

In this work we state a number of theorems about fuzzy (quasi-)pseudometrizable algebraic structures. Our most useful results are: (1) a fuzzy semitopological group whose topology is induced by a left-invariant fuzzy (quasi-)pseudometric, then it is a fuzzy (paratopological) topological group, (2) if the topology on a semigroup S is induced by an invariant fuzzy quasi-pseudometric, then S is a fuzzy topological semigroup, and (3) the same conclusion is valid for a left-invariant fuzzy quasi-pseudometric on a monoid G such that the left translations are open and the right translations are continuous at the identity e of G. By means of the standard fuzzy (quasi-)pseudometric associated to a (quasi-)pseudometric d, our results apply in the case of semitopological groups, semigroups and monoids in order to obtain new results that allow us to generalize and to strengthen previous outcomes.