👉 In mathematics and logic, a nullifier or negation is an operator that reverses a conditional statement. It is used to either negate (eliminate) a statement about something's truth value, or to express the opposite of it. For example: - In mathematical logic, if you have a statement such as "If x > 0, then y < 0," and you want to negate this statement by taking away all x's from both sides, you would write: -