Negated simple conditions
A simple condition is negated through the use of the logical operator NOT.
The negated simple condition gives the opposite truth value of the simple condition. That is, if the truth value of the simple condition is true, then the truth value of that same negated simple condition is false, and vice versa.
Placing a negated simple condition within parentheses does not change its truth value. That is, the following two statements are equivalent:
NOT A IS EQUAL TO B.
NOT (A IS EQUAL TO B).