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Re: UBL Naming Conventions & RDF

From: Jonathan Brinley <jonathanbrinley@gmail.com>
Date: Fri, 8 Jul 2005 13:20:12 -0500
Message-ID: <be81683050708112076f16fbb@mail.gmail.com>
To: semantic-web@w3.org

> <Person><has><Parent rdf about='uri'/></has></Person>.

> <Person><has><Acquaintance rdf:about='uri'/></></>

What does <has> mean here?  Does our person have a Parent in the same
way that he has an Acquaintance?  All that I can gather from the
predicate is that the subject is in some vague way related to the
object.

Also, consider the following (please, forgive the awful, unstandardized syntax):
<Person rdf:about="&ex;Person1"><has><Parent rdf:about="&ex;Person2">
<Person rdf:about="&ex;Person3"><has><Acquaintance rdf:about="&ex;Person2">

What do we know, then:
Person1 and Person3 are members of the class Person
Person2 is a member of the classes Parent and Acquaintance
Person1 and Person3 have a <has> relationship to Person 2

The exact same graph can be drawn from:
<Person rdf:about="&ex;Person1"><has><Acquaintance rdf:about="&ex;Person2">
<Person rdf:about="&ex;Person3"><has><Parent rdf:about="&ex;Person2">

This class of the object says nothing about the relationship that
holds between the subject and the object.

Have a nice day,
Jonathan Brinley



> 
> 3. Frank Manola notes that some don't use <hasX> implying he has seen <has><X>
> before.... who would they be I am wondering. Other than rdf:type, *all* OWL
> property names confabulate the predicate verb with a predicate noun, consistent
> with fundamental RDF architecture, Fact=Subject+Predicate. This architecture
> clearly results in a "RDF Naming Convention". Frank also states that "the
> 'hasFoo' approach has the merit of indicating the directionality of the
> relationship" a feature which, I believe, is preserved by <has><X>. Like Frank,
> I also value readability highly, and therefore am cautious about designs which
> eliminate predicate verbs from markup altogether. Frank also suggests I take
> this question over to the SWBP list (see below).
> 
> -------------------
> Why is this issue more than just a syntactic game? My problem stems from the
> fact that domains (and ranges) can be specified only for properties, not for
> classes. These nouns indicate sets of Things; they are undoubtedly classes. But,
> how does one specify that for instance, only a LivingThing can have a Parent?
> One cannot with OWL DL, but of course in OWL Full, I can create metaclasses such
> as Noun (subClassOf Class), Verb and Preposition (subClassOf Property), and
> DirectObject (subClassOf Noun and subClassOfProperty). Then, define 'Parent' as
> an instance of a Noun (and subClassOf Role), and define 'CustodialParent' and
> 'BiologicalParent' as instances of DirectObject, with range (or subClassOf)
> 'Parent' and with domain (sic) Person. This yields what to me is a most sensible
> statement: <Person><has><CustodialParent rdf:about='uri'/></></>.
> 
> In other words, the architecture is that the name of the direct object is
> *never* a type of object (Parent) but rather it is *always* its functional role
> with respect to the subject of the 'statement' being made. Here, CustodialParent
> reflects the role that a Parent plays with respect to the Person. Note also that
> CustodialParent can easily function anonymously....
> <Person><CustodialParent/></Person> can imply the <has> predicate verb. Finally,
> note that the range for <has> is flaccid: it is just a DirectObject.
> 
> So the conclusions I'm presently drawing are
> (1) it is not  possible to create a UBL conforming ontology using OWL Lite or
> OWL DL
> (2) in OWL Full, a grammatical foundation is both feasible and immediately
> useful
> 
> With regard to the suggestion that this be handled by SWBP, I would be fine
> doing so but am wondering also whether the matter that RDF has yet to define
> constructs like <Noun>, <Verb>, and <DirectObject> has traction here in
> semantic-web, since I'd think the reach of the SW would be considerably greater
> should UBL requirements be accommodated as soon as possible. *RDF Naming
> Conventions* is clearly a ripe issue for SWBP but your concurrence with (1) and
> (2) above would provide excellent guidance for that discussion.
> 
> Thanks,
> John McClure
> 
> PS I admit to being 'just' an XML guy, so please bear with me if I mangle any N3
> expressions!
> 
> 
> 


-- 
Jonathan M. Brinley

jonathanbrinley@gmail.com
http://purl.org/net/brinley
Received on Friday, 8 July 2005 18:20:23 UTC

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