- From: Steven Gollery <sgollery@cadrc.calpoly.edu>
- Date: Thu, 07 Feb 2002 13:30:52 -0800
- To: www-rdf-logic@w3.org
Ken, Thank you -- that seems reasonable. Just to make sure that I'm understanding, here's some DAML that I think implements what you're describing: <daml:Class rdf:ID="Point"> </daml:Class> <daml:Class rdf:ID="VertexList"> <rdfs:subClassOf rdf:resource="daml:list"/> <rdfs:subClassOf> <daml:Restriction> <daml:onProperty rdf:resource="daml:item"/> <daml:toClass rdf:resource="#Point"/> <daml:minCardinality>3</daml:minCardinality> </daml:Restriction> </rdfs:subClassOf> </daml:Class> I think that restricts the class of the items to Point and the number of items to 3 or more. Is that right? Thanks again, Steve Ken Baclawski wrote: > The daml:item property relates a list to each of its elements. One can > impose a daml:minCardinality restriction on the daml:item property to > ensure that the number of vertices in a polygon is at least 3. > > Ken Baclawski > Ken@Baclawski.com > UBOT Project > > On Wed, 6 Feb 2002, Steven Gollery wrote: > > > I'm working on an ontology in DAML that includes some geometric > > concepts. I would like to be able to somehow define a property Vertices > > whose domain is the Polygon class and whose range is ordered collections > > of instances of the Point class, where the length of the ordered > > collection is at least three. > > > > It would be fairly straightforward to say that each Polygon must have at > > least three values of a Vertex property which is restricted to class > > Point, but that would lose the idea the vertices have an order -- the > > order is obviously a fundamental part of the semantics for the polygon. > > > > Does DAML provide any way to restrict the number of elements in a list? > > Or is there some other way to do what I need here? > > > > Thanks in advance, > > > > Steve Gollery > > sgollery@cadrc.calpoly.edu > > > >
Received on Thursday, 7 February 2002 16:29:22 UTC