index.md (431B)
1 +++ 2 title = 'Semantic entailment' 3 +++ 4 # Semantic entailment 5 ϕ₁, …, ϕn ⊨ Ψ 6 7 A formula Ψ is semantically entailed by premises (ϕ₁, …, ϕn) if every valuation that makes premises true makes Ψ true. 8 9 counterexample makes premises true but not conclusion 10 11 if ϕ ⊨ Ψ and Ψ ⊨ ϕ, ϕ ≡ Ψ 12 13  14 