Definition:Real Interval/Open

Definition
Let $a, b \in \R$. The open (real) interval from $a$ to $b$ is defined as:


 * $\openint a b := \set {x \in \R: a < x < b}$

Also see

 * Definition:Closed Real Interval
 * Definition:Half-Open Real Interval
 * Definition:Unbounded Open Real Interval
 * Definition:Unbounded Closed Real Interval


 * Definition:Open Rectangle, a generalization to higher dimensional spaces