Nesting of intersectionOf and unionOf

Hi,
 
I need your help on a syntactical problem (if it is one at all).
 
In mapping the data model of ISO 15926-2 to OWL I stumbled over a situation
that I had to solve with a nesting of a unionOf inside an intersectionOf,
and I would like to know whether or not that is allowed. If not, what is the
solution?
 
An example is:
 
 <owl:intersectionOf rdf:parseType="Collection"> 
 <owl:Class rdf:about="#ParticipatingRoleAndDomain"/> 
 <owl:unionOf rdf:parseType="Collection"> 
 <owl:Class rdf:about="#ClassOfArrangedIndividual"/> 
 <owl:Class rdf:about="#ClassOfEvent"/> 
 <owl:Class rdf:about="#ClassOfPeriodInTime"/> 
 <owl:Class rdf:about="#IndividualDimension"/> 
 <owl:Class rdf:about="#Property"/> 
 <owl:Class rdf:about="#Status"/> 
 </owl:unionOf>
 </owl:intersectionOf>
 
and another, even more complex:
 
 <owl:intersectionOf rdf:parseType="Collection"> 
 <owl:Class rdf:about="#ClassOfActivity"/> 
 <owl:Class rdf:about="#ClassOfFeature"/> 
 <owl:Class rdf:about="#ClassOfInformationObject"/> 
 <owl:Class rdf:about="#ClassOfOrganization"/> 
 <owl:unionOf rdf:parseType="Collection"> 
 <owl:Class rdf:about="#ClassOfInanimatePhysicalObject"/> 
 <owl:Class rdf:about="#ClassOfOrganism"/> 
 </owl:unionOf>
 <owl:unionOf rdf:parseType="Collection"> 
 <owl:Class rdf:about="#ClassOfAtom"/> 
 <owl:Class rdf:about="#ClassOfBiologicalMatter"/> 
 <owl:Class rdf:about="#ClassOfCompound"/> 
 <owl:Class rdf:about="#ClassOfCompositeMaterial"/> 
 <owl:Class rdf:about="#ClassOfFunctionalObject"/> 
 <owl:Class rdf:about="#ClassOfInformationPresentation"/> 
 <owl:Class rdf:about="#ClassOfInformationRepresentation"/> 
 <owl:Class rdf:about="#ClassOfMolecule"/> 
 <owl:Class rdf:about="#ClassOfParticulateMaterial"/> 
 <owl:Class rdf:about="#ClassOfSubAtomicParticle"/> 
 <owl:Class rdf:about="#CrystallineStructure"/> 
 <owl:Class rdf:about="#Phase"/> 
 </owl:unionOf>
 </owl:intersectionOf>
 
Please don't bother with the details, I only need confirmation that this is
legal OWL Full.
 
Can you help?
 
Kind regards,
Hans
_______________________ 
Hans Teijgeler
ISO 15926 specialist
 <http://www.InfowebML.ws> www.InfowebML.ws
 <mailto:hans.teijgeler@quicknet.nl> hans.teijgeler@quicknet.nl
phone +31-72-509 2005