Errata/E11

From OWL
Jump to: navigation, search
4) http://www.w3.org/TR/2009/REC-owl2-syntax-20091027/#Object_Property_Cardinality_Restrictions

The first sentence in the description below of cardinality restrictions is incorrect with the second sentence:

All cardinality restrictions can be qualified or unqualified: in the former case, the cardinality restriction only applies to individuals that are connected by the object property expression and are instances of the qualifying class expression; in the latter case the restriction applies to all individuals that are connected by the object property expression (this is equivalent to the qualified case with the qualifying class expression equal to owl:Thing). The class expressions ObjectMinCardinality, ObjectMaxCardinality, and ObjectExactCardinality contain those individuals that are connected by an object property expression to at least, at most, and exactly a given number of instances of a specified class expression, respectively.

In the first sentence, "individuals that are connected by the object property expression" refers to the individuals in the domain of the OPE.
Thus, "individuals that are connected by the object property expression and are instances of the qualifying class expression" would suggest that the qualifying class expression applies to individuals in the domain of the OPE whereas the last sentence clearly suggests that the specified class expression (presumably the same as the 'qualifying class expression' mentioned earlier) are in the range of the OPE.

Perhaps the following might help some readers:

Given:

Object{Min,Max,Exact}Cardinality( nNI OPE CE )

Then the following should be true:

SubClassOf( Object{Min,Max,Exact}Cardinality( nNI OPE CE ) ObjectPropertyDomain( OPE ) )
SubClassOf( CE ObjectPropertyRange( OPE ) )

As with ObjectSomeValuesFrom, ObjectAllValuesFrom, and ObjectHasValue class expressions, cardinality class expressions make no (direct) statements about the domain or range of an object property expression.