Some comments on OWL S&AS


[2.1. Ontologies 

There are two built-in classes in OWL,....
 The class with identifier owl:Thing is the class of all individuals, and is part of OWL Lite. The class with identifier owl:Nothing is the empty class. 

It should be explicitly specified whether or not owl:Nothing is included in OWL Lite. 
It would be nice and elegant to include owl:Nothing in OWL Lite if there is no harm to do so.


[2.3. Axioms
However, **most information about properties** is more naturally expressed in restrictions, which allow local range and cardinality information to be specified. 
Restrictions are about to define new classes, not to specify properties. So the above sentence should be modified if possible. 


[ OWL Lite Restrictions

cardinality ::= 'minCardinality(0)' | 'minCardinality(1)' |
            | 'maxCardinality(0)' | 'maxCardinality(1)' |
            | 'cardinality(0)'    | 'cardinality(1)'

There are two reduantant symbols '|'.

4. About individual

Just suggestion:
The named individual and the anonymous individual should be explicitly separated. There are some essential differnce between facts about named individuals and the ones about anonymous individuals. 

Yuzhong Qu
Dept.Computer Science and Engineering
Southest University, Nanjing, China

Received on Saturday, 5 April 2003 09:34:11 UTC