Welcome Propositional Logic Precedence/Order of Evaluation Application Usage Examples

Examples of Tautologies and Contradictions

Try copying and pasting these statements into the application using the keyboard shortcuts Ctrl+C (copy) and Ctrl+V (paste).

Tautologies:

P & Q => P
P => P v Q v R
((P => Q) & (Q => R)) => (P => R)
~(P & Q) <=> (~P v ~Q)
~(P v Q) <=> (~P & ~Q)
(P + Q) <=> ~(P <=> Q)

Contradictions:

P & ~P
P <=> ~P
~(P => (Q => P))
(P v Q) & ~(~Q => P)
(P v Q => R) <=> ~(R v ~(~P => Q))
(P <=> Q) <=> ~((P => Q) & (Q => P))