Valid vs satisfiable Let a be a wff and i an interpretation 1. FI A iff w a is not satisfiable in I 2.A iff w a is not satisfiable 3. a is satisfiable in i iff n a is not valid in z 4. A is satisfiable iff n a is not valid 5. Fi A iff Fi vc a 6. A iff E A 7. A is satisfiable in i iff 3x a is satisfiable in I 8. a is satisfiable iff c a is satisfiable Logic in Computer Science- p.11/18Valid vs Satisfiable Let A be a wff and I an interpretation. 1. |=I A iff ∼ A is not satisfiable in I. 2. |= A iff ∼ A is not satisfiable. 3. A is satisfiable in I iff ∼ A is not valid in I. 4. A is satisfiable iff ∼ A is not valid. 5. |=I A iff |=I ∀xA. 6. |= A iff |= ∀xA. 7. A is satisfiable in I iff ∃xA is satisfiable in I. 8. A is satisfiable iff ∃xA is satisfiable. Logic in Computer Science – p.11/18