The two definitions () and () define the equivalent of the truth tables for the ~ (NOT) and → (IMPLICATION) connectives of his system. The first one derives F ≠ T and T ≠ F, in other words " v("A") does not mean v(~"A")". Definition () specifies the third row in the truth table, and the other three rows then come from an application of definition (). In particular () assigns the value F (or a meaning of "F") to the entire expression. The definitions also serve as formation rules that allow substitution of a value previously derived into a formula: