3. UML and OCL integration UML Meta-Model EMOF / Ecore Meta-Model UML Model EMOF / Ecore Model UML Edit Export conforms to conforms to UML Model UML Model OCL for EMOF Model OCL Edit Export OCL for UML Model OCL Meta-Model conforms to conforms to OpaqueExpression ExpressionInOcl generalises ExpressionInOcl ???