From: Ian Horrocks (horrocks@cs.man.ac.uk)
Date: 09/07/01
On September 4, Mike Dean writes: > > In http://www.daml.org/2001/03/daml+oil.daml, TransitiveProperty and > > UnambiguousProperty are both sub-classes of ObjectProperty, but > > UniqueProperty is a sub-class of rdf:Property. This seems like a bug to me, > > or am I missing something? > > TransitiveProperty deals with chaining of instances, so it > makes sense to only apply it to ObjectProperties. > UniqueProperty is basically an idiom for cardinality > constraints, and can be applied to any property. > > It seems to me that UnambiguousProperty could also apply to > any property, e.g. a serial number (xsd:string or > xsd:decimal) could unambiguously identify a part. In fact, > I think the most common usage is with Datatype properties. UnambiguousProperty is is basically an idiom for a cardinality constraint on the inverse property applied to all objects at the "value end" of the property. As only daml objects can be instances of such restrictions (i.e., can be instances of daml classes), UnambiguousProperty is a subClassOf ObjectProperty. Ian > I'm cc'ing some other folks to see if I missed something. > > > PS Was great to meet up with you in Seattle. Hope you enjoyed the rest of > > the conference. > > Likewise! I hope you also had a good holiday. > > Mike
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