*a*and

*b*be real numbers. We write

*(a,b) = {x *in **R** : *a < x < b}*.

This is an open interval or segment of the real line. See also closed interval.

See all of open interval, no other writeups in this node.

Let *a* and *b* be real numbers. We write

*(a,b) = {x *in **R** : *a < x < b}*.

This is an open interval or segment of the real line. See also closed interval.