- 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 URI references
from RDF, RDFS, OWL or XML Schema datatypes.
-
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.
-
No blank node occurs as the object of more than one
triple.
- No directed cycle of blank nodes
occurs.
-
Every blank node with explicit type
rdf:List
is the object of exactly one triple.
-
Every builtin uriref is assigned to one of
its listed categories, or to itself.
-
Every other uriref is assigned to one of the following
categories: