Subject: Re: Saying anything about anything: Comments on Harle & Fensel Resent-Date: Wed, 5 Jan 2000 12:43:06 -0500 (EST) Resent-From: www-rdf-interest@w3.org Date: Wed, 05 Jan 2000 18:42:50 +0100 From: Jonas Liljegren To: RDF Intrest Group CC: Stefan Decker References: 1 subject: Re: Saying anything about anything: Comments on Harle & Fensel Stefan Decker wrote: > > Sure. The problem comes when properties describe a "role", which can > be filled by different ranges for different classes. ... > Instead one has to ensure that a property is unique for each domain > (e.g. by adding a class-prefix), which is redundant > (and this was the main point in the paper). > (e.g. something like hasHumanChild, hasDogChild). > > The problem is, that a property can only be used in one class, but is > globally visible for all classes. Many properties CAN be used with many classes. You don't have to encode that the child of a human is a human. That can be explicitly stated by the type of the child resource. But if you want to differ between human childs and dog childs, then you should add this to the property schema. hasHumanChild and hasDogChild can be subClassOf hasChild. It should not be considered redundant. In RDF, there is no hasHumanChild property. The propertys real name could be something like http://my.org/rdf/class/Human#hasChild. The label of this property could be "has child", and the domain and range could be http://some.other.org/rdf/class#Human. This would result in that the visibel property name would be "has child", but the RDF application would know that the range is only humans. And any application could gain the information that this is a sub property of the well known (generic) 'hasChild' property, that it know so well. -- / Jonas - http://paranormal.o.se/perl/proj/rdf/schema_editor/