http://www.openhealth.org/XSet#String http://www.openhealth.org/XSet#String http://www.w3.org/2000/01/rdf-schema#Literal http://www.openhealth.org/XSet#Char http://www.openhealth.org/XSet#Seq http://www.openhealth.org/XSet#Alt http://www.openhealth.org/XSet#String http://www.openhealth.org/XSet#Seq http://www.openhealth.org/XSet#Seq http://www.w3.org/2000/01/rdf-schema#Class define property for each production