Discrete Mathematics Use inference rules to show that the fo
Discrete Mathematics.
Use inference rules to show that the following Boolean expression is always true (a tautology).
Solution
Tautology :-
A Boolean expression is a tautology if and only if for all possible assignments of truth values to its variables its truth value is True.
Solution :-
Given Boolean Expression :- (( P & ¬( ¬P Q)) (P & Q)) P
Let us consider...
( P & ¬( ¬P Q)) = A
(P & Q) = B
Therefore... (( P & ¬( ¬P Q)) (P & Q)) = A B
Finally... (( P & ¬( ¬P Q)) (P & Q)) P = (A B) P
| P | ¬P | Q | (¬PQ) | ¬(¬PQ) | A | B | A B | (A B) P |
| TRUE | FALSE | TRUE | TRUE | FALSE | FALSE | TRUE | TRUE | TRUE |
| TRUE | FALSE | FALSE | FALSE | TRUE | TRUE | FALSE | TRUE | TRUE |
| FALSE | TRUE | TRUE | TRUE | FALSE | FALSE | FALSE | FALSE | TRUE |
| FALSE | TRUE | FALSE | TRUE | FALSE | FALSE | FALSE | FALSE | TRUE |
