*Definition [#z99a3711] -A topological space (X, τ) is said to be a Urysohn space if every pair of distinct points have disjoint closed neighbourhoods. *Property [#qceaf0eb] - Urysohn ⇒ [[strongly Hausdorff]]. - Urysohn ⇒ [[pre-Urysohn]]. [2] *Reference [#i72fbdf3] +Porter, J. R., ''Strongly Hausdorff spaces''. Acta Math. Acad. Sci. Hungar. 25 (1974), 245–248. +Paul Ramprasad, Bhattacharyya P., ''On pre-Urysohn spaces''. (English summary), Bull. Malaysian Math. Soc. (2) 22 (1999), no. 1, 23–34.