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Syntax Definition wi 4
Description: If and are wff's, so is or " implies ." Part of the recursive definition of a wff. The resulting wff is (interpreted as) false when is true and is false; it is true otherwise. (Think of the truth table for an OR gate with input connected through an inverter.) The left-hand wff is called the antecedent, and the right-hand wff is called the consequent. In the case of , the middle may be informally called either an antecedent or part of the consequent depending on context.
Ref Expression
Ref Expression

This syntax is primitive. The first axiom using it is ax-1 5.

Colors of variables: wff set class
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