Id Assertion MAY consume well-formed instance documents which do not satisfy local-schema validity against the originating document. MUST be able to consume any well-formed document which satisfies local-schema validity against the originating document exposing all of the element node and attribute node content in the data model. MUST produce a data model exposing all of the element node and attribute node content constrained by the originating document. MAY allow the production of well-formed instance documents containing values exposed in the data model which do not satisfy local-schema validity against the originating document. MUST be able to produce well-formed instance documents which satisfy local-schema validity against the originating document containing values exposed in the data model. MUST be able to process any document conforming to this specification