Definition
Let be a set of propositional formulas (finite or infinite) and let be a proposition. We say that is a (semantic) consequence of if and only if for every valuation such that , we have .
Let Γ be a set of propositional formulas (finite or infinite) and let φ be a proposition. We say that φ is a (semantic) consequence of Γ if and only if for every valuation V such that V⊨Γ, we have V⊨φ.