Urysohn
Description: For all $a, b \in X$ there exists a continuous function $f: X \to [0,1]$ such that $f(a) = 0$ and $f(b) = 1$.
Description: For all $a, b \in X$ there exists a continuous function $f: X \to [0,1]$ such that $f(a) = 0$ and $f(b) = 1$.