RDF statements also have a formal meaning which determines, with mathematical precision, the conclusions (or entailments) that machines can draw from a given RDF graph. The RDF Semantics [RDF- SEMANTICS] document defines this formal meaning, using a technique called model theory for specifying the semantics of a formal language. [RDF-SEMANTICS] also defines the semantic extensions to the RDF language represented by RDF Schema, and by individual datatypes. In other words, the RDF model theory provides the formal underpinnings for all RDF concepts. Based on the semantics defined in the model theory, it is simple to translate an RDF graph into a logical expression with essentially the same meaning.