Syntax	not
Description	The not (boolean negation) operator produces the opposite of a true/false value. For example, not (x >y) is equivalent to x <= y.
Example	var error : boolean := false var success : boolean … success := not error % success becomes the opposite of error
Details	The not operator takes true and produces false and takes false and produces true. The not operator can be written as ~. See also the boolean type, prefix operators, and precedence of operators. The not operator can be applied to sets.