Intervals ( open, closed intervals, Semi open/closed interval)

 Intervals

1) Open interval and Closed interval

Examples :

1. Open bracket

(1,2) or ]1,2[ = x∊R : 1<x<2  ( 1 and 2 are not included)

2. Closed square brackets

[1,2] = x∊ R : 1<=x<=2 ( 1 and 2 are included)

2) Semi-open or Semi-closed interval