This library provides an simple representation of a half-open [x,y) interval defined on set of numbers. That is if you have a set of something that may be compared (operations == and < are defined) than you may group them into intervals.
..,-20,-19.....a...........,0,..........b........ . . . . . . . ...........,1000,...
^ ^
| |
+------------------------+
[a, b) interval
Note: The a-b interval and all other intervals represented by library a left-closed class of a half-open intervals (see here for details).