open interval
Mathematics term for an interval that does not include its endpoints, e.g. (a, b). Contrasts with 閉区間 (closed interval).
See also: 閉区間
In an open interval, the endpoints are not included.
この関数は開区間で連続である。
This function is continuous on the open interval.
Compound of 開 (open) + 区間 (interval), a direct translation of the mathematical term 'open interval'.