An open interval is an interval that does not include its end points. The open interval 
is denoted 
, although the nonstandard notation ![]a,b[](/images/equations/OpenInterval/Inline3.svg)
is sometimes also used.
Open Interval
See also
Closed Interval, Half-Closed Interval, Interval, Open Disk, Open SetExplore with Wolfram|Alpha
References
Croft, H. T.; Falconer, K. J.; and Guy, R. K. Unsolved Problems in Geometry. New York: Springer-Verlag, p. 1, 1991.Gemignani, M. C. Elementary Topology. New York: Dover, 1990.Referenced on Wolfram|Alpha
Open IntervalCite this as:
Weisstein, Eric W. "Open Interval." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/OpenInterval.html