We say that Î±1 ... Î±n entail Î² if and only if it is logically impossible for Î±1 ... Î±n to be true and Î² to be false at the same time. In SL, this means that there is no assignment of truth-values under which cally impossible for Î±1 ... Î±n are all true and Î² is false.
From RDF Semantics ( 2004-02-10) (v.), (n.). A semantic relationship between expressions which holds whenever the truth of the first guarantees the truth of the second. Equivalently, whenever it is logically impossible for the first expression to be true and the second one false. Equivalently, when any interpretation which satisfies the first also satisfies the second. (Also used between a set of expressions and an expression.)