What is False (logic)?

In logic, false or untrue is the state of possessing negative truth value or a nullary logical connective. In a truth-functional system of propositional logic, it is one of two postulated truth values, along with its negation, truth. Usual notations of the false are 0 , O , and the up tack symbol  ⊥ {\displaystyle \bot }.

Another approach is used for several formal theories , where a propositional constant ,  ⊥ {\displaystyle \bot } , is introduced, the truth value of which being always false in the sense above. It can be treated as an absurd proposition, and is often called absurdity.