Intervals of real numbers

The closed interval $[u..v]$ is the set of real numbers $x$ such that $u\le x\le v$. The open interval $(u..v)$ is the set of real numbers $x$ such that $u<x<v$. At an open endpoint, $u$ can be $-\infty$ or $v$ can be $\infty$. Half-open intervals are written as $[u..v)$ or $(u..v]$.

I’m not sure how Knuth typeset his dots to be evenly spaced.