# Definition:Real Interval/Notation/Reverse-Bracket

 $\displaystyle \left ] {\, a, b} \right [$ $:=$ $\displaystyle \set {x \in \R: a < x < b}$ Open real interval $\displaystyle \left [ {a, b} \right [$ $:=$ $\displaystyle \set {x \in \R: a \le x < b}$ Half-open on the right $\displaystyle \left ] {\, a, b} \right ]$ $:=$ $\displaystyle \set {x \in \R: a < x \le b}$ Half-open on the left