W3C home > Mailing lists > Public > www-rdf-interest@w3.org > July 2004

Re: Semantic E-mail

From: Laurian Gridinoc <laurian@gmail.com>
Date: Thu, 15 Jul 2004 10:20:15 +0000
Message-ID: <9782e33504071503203072524f@mail.gmail.com>
To: www-rdf-interest@w3.org
Cc: danny@dannyayers.com

On Thu, 15 Jul 2004 11:34:16 +0200, Danny Ayers <danny666@virgilio.it> wrote:
> >>Returning to your original example:
> >>><rdf:Property rdf:about="http://NEW/#messageid" rdfs:label="messageId"
> >>>rdfs:comment="The unique Message-Id">
> >>><rdfs:subPropertyOf rdf:resource="http://purl.org/dc/elements/1.1/identifier"/>
> >>><rdfs:seeAlso rdf:resource="http://xmlns.filsa.org/xmlns.filsa.net/emir/0.2/#messageid"/>
> >>><rdfs:seeAlso rdf:resource="http://www.openhealth.org/xmtp#Message-ID"/>
> >>><rdfs:seeAlso rdf:resource="URN:ietf:params:rfc822:message-id"/>
> >>></rdf:Property>
> >>>
> >>Would I be right in thinking that
> >>URN:ietf:params:rfc822:message-id
> >>etc. are other ways of describing a message id? To be used as:
> >>X hasMessageId Y
> >>If so, although owl:equivalentProperty might be an option, I'd be wary of using it because the alternatives might not be /quite/ the same. How about:
> >><owl:ObjectProperty rdf:about="http://NEW/#messageid" rdfs:label="messageId"
> >>rdfs:comment="The unique Message-Id">
> >><rdfs:subPropertyOf rdf:resource="http://purl.org/dc/elements/1.1/identifier"/>
> >><rdfs:subPropertyOf rdf:resource="http://xmlns.filsa.org/xmlns.filsa.net/emir/0.2/#messageid"/>
> >><rdfs:subPropertyOf rdf:resource="http://www.openhealth.org/xmtp#Message-ID"/>
> >><rdfs:subPropertyOf rdf:resource="URN:ietf:params:rfc822:message-id"/>
> >></owl:ObjectProperty>
> >>
> >>In other words, http://NEW/#messageid shares characteristics of each of
> >>these, but perhaps not all, is a specialization.
> >>
> >It is a specialization of dc:identifier, but I don't think it is ok to
> >say that an identifier is a specialization of itself (more or less).
> >And I don't think it's ok to suggest "J sameAs K" using both "J
> >subPropertyOf K" and "K subPropertyOf J"
> 
> I'm not suggesting that - the new property doesn't appear as the object
> of any of the statements. In any case, if it did I believe the
> subsumption rules would result in J owl:equivalent K, which would be
> perfectly ok (but possibly not what you wanted).
> If the other terms really are equivalent then you could use
> owl:equivalentProperty, but then why bother creating a new term when you
> could use an equivalent?

"Property equivalence is not the same as property equality.
Equivalent properties have the same "values" (i.e., the same property
extension), but may have different intensional meaning (i.e., denote
different concepts). Property equality should be expressed with the
owl:sameAs construct. As this requires that properties are treated as
individuals, such axioms are only allowed in OWL Full." [1]

This is what I'm trying to avoid - OWL Full.

> >>Again, if I'm reading the intention correctly, this is all working
> >>within the property(/class) hierarchy, and should stay comfortably
> >>within OWL DL, although I believe you will have to explictly type the
> >>referenced properties, i.e. something like:
> >>
> > > <owl:ObjectProperty
> >rdf:about="http://xmlns.filsa.org/xmlns.filsa.net/emir/0.2/#messageid"
> >/>
> >
> >The intention is promote partial understanding within the vocabulary
> >itself; not by using (mixing) volatile elements, but by referring
> >several volatile elements, having a degree of redundancy.
> >
> >I thought that this was ment to be possible with RDF Schema, and from
> >my understanding, seeAlso was created for this purpose.
> 
> If you want to use these elements within the reasoning (to enable
> partial understanding) then you'll have to describe them in terms which
> can be reasoned with. All rdfs:seeAlso provides for use in inference
> about the object is that it is an rdfs:Resource which is, as my
> grandmother use to say, neither use nor ornament.

I admit that I missed `rdfs:seeAlso rdfs:range rdfs:Resource .' as axiom.

> It depends what specific kind of partial understanding you're after, but
> RDF(S) could certainly provide some in this case. You could stay with
> RDF(S) by substituting rdf:Property for owl:ObjectProperty in the
> listing above, and doing without the explicit typing of the referenced
> terms. But I got the impression from the thread that OWL DL was wanted,
> a would  require being more specific in the description of the terms to
> which you were referring.

I would prefer to stay with the most simple solution - RDF(S), worst
case lightest OWL possible; but Josh Sled pointed that owl:sameAs
applied to classes or properties is OWL Full.
 
> The volatility issue is tricky - it's a common problem. OWL has
> versioning capability terms that could be used to manage this, though
> where individual terms may change independently OWL's per-schema
> versioning isn't really granular enough. The craftiest solution I've
> seen to this came recently from Alistair Miles and Chaals, using a
> separate little ontology for each term.

Indeed a nice solution, if you can control the schema; which is not
the case when you mix vocabularies.

[1] http://www.w3.org/TR/owl-ref/#equivalentProperty-def

Thank you,
-- 
Laurian Gridinoc
Chief Developer
GRAPEFRUIT DESIGN
www.gd.ro
Received on Thursday, 15 July 2004 06:21:06 UTC

This archive was generated by hypermail 2.3.1 : Wednesday, 5 February 2014 07:14:58 UTC