Prove the following theorem: ⊢ (P → Q) → (¬ Q → ¬ P)
Prove the following equivalence: (P ∧ Q) → R ⊣ ⊢ P → (Q → R)
Prove the following set of sentences inconsistent:
{P → (Q → R), ¬ R ∧ (P ∧ Q)
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Mauro ALLEGRANZA
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Joe Norman
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What have you tried ? What proof system you are using ? – Mauro ALLEGRANZA Apr 16 '20 at 18:38
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Hint for the first one: assume ¬ Q and derive ¬ P by contradiction. – Mauro ALLEGRANZA Apr 16 '20 at 18:39
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For the 3rd one, use truth table. – Mauro ALLEGRANZA Apr 16 '20 at 18:39