difficult to use owl:unionOf and stay in OWL2 RL or DL.

gistfile1.txt

stain@ralph-ubuntu:~/Desktop$ profilechecker test.owl --all
OWL2DLProfile: OK
OWL2ELProfile: 1 violations
OWL2Profile: OK
OWL2QLProfile: 1 violations
OWL2RLProfile: 1 violations

stain@ralph-ubuntu:~/Desktop$ profilechecker test.owl OWL2RLProfile
Use of non-superclass expression in position that requires a superclass expression: ObjectUnionOf(<http://www.semanticweb.org/stain/ontologies/2013/1/untitled-ontology-2#A> <http://www.semanticweb.org/stain/ontologies/2013/1/untitled-ontology-2#B>) [ObjectPropertyRange(<http://www.semanticweb.org/stain/ontologies/2013/1/untitled-ontology-2#a_or_b> ObjectUnionOf(<http://www.semanticweb.org/stain/ontologies/2013/1/untitled-ontology-2#A> <http://www.semanticweb.org/stain/ontologies/2013/1/untitled-ontology-2#B>)) in OntologyID(OntologyIRI(<http://www.semanticweb.org/stain/ontologies/2013/1/untitled-ontology-2>))]

test.ttl

@prefix : <http://www.semanticweb.org/stain/ontologies/2013/1/untitled-ontology-2#> .
@prefix owl: <http://www.w3.org/2002/07/owl#> .
@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
@prefix xml: <http://www.w3.org/XML/1998/namespace> .
@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
@base <http://www.semanticweb.org/stain/ontologies/2013/1/untitled-ontology-2> .

<http://www.semanticweb.org/stain/ontologies/2013/1/untitled-ontology-2> rdf:type owl:Ontology .


:a_or_b rdf:type owl:ObjectProperty ;
        
        rdfs:range [ rdf:type owl:Class ;
                     owl:unionOf ( :A
                                   :B
                                 )
                   ] .


:A rdf:type owl:Class .

:B rdf:type owl:Class .

:C rdf:type owl:Class .