Direct Formulation of OWL DL and OWL Lite Ontologies in RDF Graph Form

A finite RDF graph is an OWL DL or OWL Lite ontology in RDF graph form if and only if it meets the following conditions:

1. For every node of the graph and every URI reference used as a property or datatype at least one of the following holds:
   • It is one of the built-in OWL datatypes, rdfs:Literal, built-in OWL classes, built-in OWL annotation properties, or the built-in OWL ontology properties.
   • It is the subject of at least one triple with predicate rdf:type, and with object other than rdf:Property, rdfs:Class, owl:FunctionalProperty, owl:DeprecatedProperty, owl:DeprecatedClass. The objects of such triples are known as the explicit types of the subject.
   • It is a literal.
2. Every blank node with explicit type rdf:List or [DL only] owl:DataRange is the object of exactly one triple.
3. Any uriref which is a built-in OWL datatype or in the datatype-only vocabulary or rdfs:Literal is assigned to the category datatypeID. Any uriref which is a built-in OWL class or in the class-only vocabulary is assigned to the category classID. Any uriref which is a built-in OWL annotation property is assigned to the category annotationPropID. Any uriref which is a built-in OWL ontology property is assigned to the category ontologyPropertyID. Any uriref which is in the property-only vocabulary is assigned to one of the categories annotationPropID, dataPropID objectPropID or transitivePropID. Every uriref in the disallowed vocabulary is assigned to itself.
4. Every other uriref is assigned to one of the following categories:
   • ontologyID
   • datatypeID
   • annotationPropID
   • classID
   • individualID
   • dataPropID
   • objectPropID
   • transitivePropID
5. Every blank node is assigned to one of the following categories:
   • allDifferent
   • listOfDescription
   • listOfIndividualID
   • restriction
   • unnamedIndividual
   • [DL only] description
   • [DL only] listOfDataLiteral
   • [DL only] unnamedDataRange
6. With the given category assignments every triple in the graph appears in one of the following tables:
   • Main Lite table
   • [DL only] Main DL table
   • blank nodes of category allDifferent
   • blank nodes of category listOfDescription
   • blank nodes of category listOfIndividualID
   • blank nodes of category restriction
   • [DL only] blank nodes of category description
   • [DL only] blank nodes of category listOfDataLiteral
   • [DL only] blank nodes of category unnamedDataRange
7. Every blank node is either of category unnamedIndividual or meets the structural requirements listed below, in the appropriate table.
8. A blank node which occurs as the object of more than one triple must be of category restriction or [DL only] description.
9. Directed cycles of blank nodes may not occur in OWL Lite and in OWL DL must contain at least one triple with property owl:disjointWith or owl:equivalentClass.

Such an RDF graph which does not use any of the cases marked as DL only, is in OWL Lite.

A directed cycle of blank nodes is a sequence of triples t0, t1, ... tn, in which tn = t0, and in which the subjects and objects of all the triples are blank, and in which the object of ti is the subject of ti+1, for i from 0 to n-1.

Main Lite Table

Main DL Table

Rules for Blank Nodes of Category allDifferent

Every node of category allDifferent must fit the following pattern. For each such node, exactly one instance of each triple in the pattern must be present in the graph. There are no other triples in the graph in which such nodes are subjects.

Rules for Blank Nodes of Category listOfDescription

Every node of category listOfDescription must fit the following pattern. For each such node, exactly one instance of each triple in the pattern must be present in the graph. There are no other triples in the graph in which such nodes are subjects.

Rules for Blank Nodes of Category listOfIndividualID

Every node of category listOfIndividualID must fit the following pattern. For each such node, exactly one instance of each triple in the pattern must be present in the graph. There are no other triples in the graph in which such nodes are subjects.

Rules for Blank Nodes of Category restriction

Every node of category restriction must fit one of these patterns. For each such node, exactly one instance of each triple in the pattern must be present in the graph. There may be additional triples in which such nodes are subjects as listed in the main triple tables.

[DL only] Rules for Blank Nodes of Category description

Every node of category description must fit one of these patterns. For each such node, exactly one instance of each triple in the pattern must be present in the graph. There may be additional triples in which such nodes are subjects as listed in the main triple tables.

[DL only] Rules for Blank Nodes of Category listOfDataLiteral

Every node of category listOfDataLiteral must fit the following pattern. For each such node, exactly one instance of each triple in the pattern must be present in the graph. There are no other triples in the graph in which such nodes are subjects.

[DL only] Rules for Blank Nodes of Category unnamedDataRange

Every node of category unnamedDataRange must fit the following pattern. For each such node, exactly one instance of each triple in the pattern must be present in the graph. There may be additional triples in which such nodes are subjects as listed in the main triple tables.