RE: DAML Correction: Same Is Not A Sub Of Sub

I'm still picking the bones out of this one (though I still haven't found
the line you refer to), but of relevance may be (from the DAML ref
description [1]) :

Warning: the use of samePropertyAs is favoured over the use of equivalentTo,
since samePropertyAs is declared as a subProperty of subPropertyOf, while
equivalentTo is not. This makes the meaning of samePropertyAs at least
partly available to an RDF Schema-only agent, while the meaning of
equivalentTo is completely opaque to such an agent.

Which I suppose is saying, the DAML schema can be self-consistent without
having to be in the same space as the RDF schema.

[1] http://www.daml.org/2000/12/reference.html

---
Danny Ayers
http://www.isacat.net

<- -----Original Message-----
<- From: www-rdf-logic-request@w3.org
<- [mailto:www-rdf-logic-request@w3.org]On Behalf Of Sean B. Palmer
<- Sent: 05 May 2001 19:57
<- To: www-rdf-logic@w3.org
<- Subject: DAML Correction: Same Is Not A Sub Of Sub
<-
<-
<- [This also applies to "daml:sameClassAs".]
<-
<- In the DAML+OIL 2001 March version, it states that:-
<-
<-    daml:samePropertyAs rdfs:subPropertyOf rdfs:subPropertyOf .
<-
<- I believe this to be a "schema inconsistency", because this implies
<- that anything which is the same property as another is also a sub
<- property of it [1]. Noting that:-
<-
<-    daml:samePropertyOf daml:inverseOf daml:samePropertyOf .
<-
<- That means that:-
<-
<-    <> log:forAll :x , :y .
<-    { :x :daml:samePropertyAs :y }
<-    log:implies
<-    { :x rdfs:subPropertyOf :y . :y rdfs:subPropertyOf :x } .
<-
<- Which goes against the RDF Schema specification, which states, "A
<- property can never be declared to be a subproperty of itself, nor of
<- any of its own subproperties".
<-
<- However, it is still fair to say that:-
<-
<-    daml:samePropertyAs rdfs:subPropertyOf daml:equivalentTo .
<-
<- And that:-
<-
<-    rdf:Property rdfs:subClassOf
<-       [ a daml:Restriction;
<-         daml:onProperty daml:samePropertyAs;
<-         daml:toClass rdf:Property ] .
<-
<- It's interesting adding constraints to other people's terms w.r.t.
<- your own terms...
<-
<- Apologies if this has been raised a million times before.
<-
<- [1] "If some property P2 is a subPropertyOf another more general
<- property P1, and if a resource A has a P2 property with a value B,
<- this implies that the resource A also has a P1 property with value B."
<- viz.
<-
<- { :p2 rdfs:subPropertyOf :p1 . :x :p2 :y . }
<- log:implies
<- { :x :p1 :y } .
<-
<- Which means that:-
<-
<- { daml:samePropertyAs rdfs:subPropertyOf rdfs:subPropertyOf .
<-    :x rdfs:samePropertyAs :y . }
<- log:implies
<- { :x rdfs:subPropertyOf :y } .
<-
<- { daml:samePropertyAs rdfs:subPropertyOf rdfs:subPropertyOf .
<-    :y rdfs:samePropertyAs :x . }
<- log:implies
<- { :y rdfs:subPropertyOf :x } .
<-
<- --
<- Kindest Regards,
<- Sean B. Palmer
<- @prefix : <http://webns.net/roughterms/> .
<- :Sean :hasHomepage <http://purl.org/net/sbp/> .
<-

Received on Saturday, 5 May 2001 11:07:55 UTC