The syntax for ranges of values follows this format.

bound type lower bound (comma) upper bound bound type
[ or ( value1 , value2 ) or ]

The following table describes the meaning of each syntax element.

Symbol Meaning
( value is greater than value1
[ value is greater than or equal to value1
value1 lower bounding value or empty if unbounded
, comma separates value1 and value2
value2 upper bounding value or empty if unbounded
) value is less than value2
] value is less than or equal to value2

Examples

Range Defined Set
[1,3] 1 <= value <= 3
(1,3] 1 < value <= 3
[1,3) 1 <= value < 3
(1,3) 1 < value < 3
(a,d) strings greater than a and less than d (for example, aardvark and czar would fit within these bounds)
( ,1] value <= 1 (empty means unbounded)
[3, ) value >= 3 (empty means unbounded)

For more information on intervals see the article on Wikipedia.