A '''metric space''' is a pair (''X'', ''d'') where ''X'' is a [[topological space]] and ''d'' is a [[Metric (mathematics)|metric]].
+
A '''metric space''' is a pair (''X'', ''d'') where ''X'' is a [[topological space]] and ''d'' is a [[Metric (mathematics)|metric]]. All metric spaces are [[Hausdorff spaces]]