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RE: [URW3 public] Re: [URW3] ... three questions based on the last telecon

From: Giorgos Stoilos <gstoil@image.ece.ntua.gr>
Date: Mon, 16 Jul 2007 14:55:21 +0300
Message-Id: <200707161155.l6GBtGAl023012@manolito.image.ece.ntua.gr>
To: "'Ivan Herman'" <ivan@w3.org>
Cc: <Peter.Vojtas@mff.cuni.cz>, "'Ken Laskey'" <klaskey@mitre.org>, <public-xg-urw3@w3.org>, <mpool@convera.com>



> -----Original Message-----
> From: Ivan Herman [mailto:ivan@w3.org]
> Sent: Monday, July 16, 2007 2:33 PM
> To: Giorgos Stoilos
> Cc: Peter.Vojtas@mff.cuni.cz; 'Ken Laskey'; public-xg-urw3@w3.org;
> mpool@convera.com
> Subject: Re: [URW3 public] Re: [URW3] ... three questions based on the
> last telecon
> 
> 
> 
> Giorgos Stoilos wrote:
> > Hi Peter,
> >
> > Triples syntax is very specific to the RDF standard and *not* to every
> W3C
> > standard. For example, triples syntax is not used in OWL (the standard
> > describes a mapping to RDF graphs but a) it is very limited and cannot
> > capture the OWL Semantics b) other syntaxes are preferred),
> 
> ??? why is the mapping limited?
> 
> Also: OWL is not equal to OWL-DL. OWL Full is fully described and
> defined in terms of an extension of RDF semantics, and the there is a
> very clear mapping between the OWL DL semantics and the corresponding
> OWL Full semantics.
> 
> However: we indeed have to separate two things. There is a 'syntax',
> essentially RDF/XML, which is nothing more than what it says: syntax.
> And there is the triple model. Indeed, in some cases other _syntaxes_
> are preferred. But that is a secondary issue in my view.
> 

Sorry, I only had OWL DL in mind. So triples syntax (and not the mapping) is
limited in the sense that when mapping OWL DL to triples one would require
to use roles and concepts in unusual places, like in the subject or object
position.
 
> >                                                              while RIF
> will
> > not care about triples syntax at all.
> >
> 
> This _may_ become correct if you refer to the RDF/XML syntax. It is not
> correct if you refer to the model of RDF triples.

Is there going to be a "RIF map to RDF graphs"?.

-gstoil

> 
> > I think you are mixing two issues here.
> > 1) The specification of an uncertainty ontology, which describes the
> > concepts and their relations, i.e. the schema, i.e. the TBox. So I don't
> see
> > why we should add instances (ABox) in the ontology. At least in my
> > understanding the Ontology is *not* meant to describe how to capture
> > uncertainty in practice.
> > 2) How to extend ontology languages, like OWL, to add uncertainty. Then
> we
> > should take into account instances and thus the ABox and thus your
> example
> > below has a purpose.
> > So I don't understand how reification fits with the Uncertainty
> Ontology.
> >
> > Now, taken that triples are used in RDF (and not in OWL) I see your
> example
> > below as an effort to extend RDF as to capture uncertainty, or about
> > serializing an Uncertainty-OWL extension to RDF triples, which I don't
> see
> > how is relevant.
> >
> > -gstoil
> >
> >> -----Original Message-----
> >> From: public-xg-urw3-request@w3.org [mailto:public-xg-urw3-
> request@w3.org]
> >> On Behalf Of Peter Vojtas
> >> Sent: Monday, July 16, 2007 11:24 AM
> >> To: Ken Laskey
> >> Cc: public-xg-urw3@w3.org; mpool@convera.com
> >> Subject: [URW3 public] Re: [URW3] ... three questions based on the last
> >> telecon
> >>
> >>
> >> Dear colleaguess (sent to public list and separately to KL and MP),
> >>
> >> as I have pointed in the ontology page in Top Level comments by P.
> >> Vojtas is there a mistake?, see
> >> http://www.w3.org/2005/Incubator/urw3/wiki/is_there_a_mistake%3F
> >>
> >> by W3C standards, basic information unit is a triple (subject,
> >> predicate, object) which can be true or false in a structure (to avoid
> >> discussion whether it is a sentence or proposition, w3c uses
> statement).
> >>
> >> see e.g. http://www.w3.org/TR/rdf-primer/ for following example
> >>
> >> http://www.example.org/index.html has a creation-date whose value is
> >> August 16, 1999
> >>
> >> here we can use reification for another writing asigning an identifier
> >> to the statement
> >>
> >> ex:triple1	rdf:type	rdf:Statement
> >> ex:triple1	rdf:subject 	http://www.example.org/index.html
> >> ex:triple1	rdf:predicate
> 	http://purl.org/dc/elements/1.1/creator
> >> ex:triple1	rdf:object 	http://www.example.org/staffid/85740
> >> ex:triple1	ex:creator	http://www.example.org/staffid/85741
> >>
> >> THIS CONSTRUCTION IS VERY USEFULL IN OUR CASE
> >>
> >> especialy in our ontology discussion the triple
> >>
> >> urw3:Sentence  	urw3:hasUncertainty  urw3:Uncertainty
> >>
> >> should be by my opinion rewritten as
> >>
> >> urw3:triple2	rdf:type	rdf:Statement
> >> urw3:triple2	rdf:subject 	urw3:Sentence
> >> urw3:triple2	rdf:predicate 	urw3:hasUncertainty
> >> urw3:triple2	rdf:object 	urw3:Uncertainty
> >> urw3:triple2	ex:creator	urw3:Mitch
> >>
> >> and instance ( consider also an "instance"  ex:triple1
> >> urw3:hasUncertainty  urw3:0.9)
> >>
> >> as, e.g.
> >>
> >> urw3:triple3	rdf:type	rdf:Statement
> >> urw3:triple3	rdf:subject 	ex:triple1
> >> urw3:triple3	rdf:predicate 	urw3:hasUncertainty
> >> urw3:triple3	rdf:object 	urw3:0.9
> >> urw3:triple3	ex:creator	urw3:Peter
> >> urw3:triple3	urw3:tool	urw3:Bayes
> >>
> >> The example with the german sentence (Mathias can help) is very usefull
> >> (words morgen and Morgen are problematic) because it shows what can
> >> happen. MP assigns an uncertainty to his own translation by expression
> >> "if I've translated correctly". Nevertheless, by my opinion "Es regnet
> >> morgen" is a problematic sentence because "Es regnet" is about present
> >> and "morgen" with lower case m in the begining means tomorrow, it is an
> >> adverb. So a problem accurs, what to do with a gramaticaly wrong
> >> sentence (note that the word sentence I use here in the linguistical
> >> sense, which in the W3c terminology can by defined appropriately by
> >> corresponding triples, by defining predicates like subject, verb,
> >> object, mode (manner), place and time). I would say either "Es regnet
> >> heute morgen" or "Es wird morgen regnen".
> >>
> >> Sorry for such a long mail, concluding I would like to say, please let
> >> us use w3c terminology (arguing for necessity of an extensions of
> >> standards we need be compatible with current standards). Next, the
> above
> >> example shows we need to define our own prefix and rdf vocabulary for
> >> uncertainty ontology.
> >>
> >> Greetings Peter
> >>
> >>
> >>
> >>>     *From:* Mike Pool
> >>>     *Sent:* Friday, July 13, 2007 3:25 PM
> >>>     *To:* public-xg-urw3-request@w3.org
> >>>     *Subject:* three questions based on the last telecon.
> >>>
> >>>     Hi, all:
> >>>
> >>>     We've been having some great discussions during the meetings and
> I'd
> >>>     like to pick up a few threads that came up in the last meeting.  I
> >>>     reread these as I was trying to write up the minutes:
> >>>
> >>>     1)
> >>>     Peter suggested that we use w3c standards as our guide for the
> >>>     meaning of 'proposition'.  Peter, do you know if this is defined
> >>>     somewhere by the w3C.  Could you point us to the definition?
> >>>
> >>>     2)
> >>>     I argued that propositions, in the sense of the meaning of a
> >>>     sentence that is invariant through all the paraphrases and
> >>>     translations of the sentence, rather than assertions or sentences
> as
> >>>     the kinds of things that hold probability values.
> >>>
> >>>     Kathy noted in the meeting that a problem with this definition is
> >>>     that a system might assign different uncertainty values to 2
> >>>     different logically equivalent sentences.   I can imagine that
> this
> >>>     is possible, but where it occurs I would think it nothing more
> than
> >>>     a weakness in the system, not in the definition I've suggested.
> For
> >>>     example, I might misunderstand 'Es regnet morgen' as 'it will rain
> >>>     this morning' rather than 'it will rain tomorrow' (if I've
> >>>     translated correctly) and assign it a different probability value
> >>>     than that which I'm assigning to 'it will rain tomorrow'.  But I
> >>>     think that anyone who observed my doing this would point out that
> >>>     it's a contradiction, i.e., that since these things have the same
> >>>     meaning, I'm obligated to assign them the same probability value.
> >>>      In other words, it is in virtue of their representing the same
> >>>     proposition that I'm obligated to assign them the same probability
> >>>     value.    So, I think this only helps to underscore the fact that
> >>>     when we explore our intuitions, we believe that propositions are
> the
> >>>     real p.v. holders.
> >>>
> >>>     3)
> >>>     Anne, you said at one point that "not all beliefs can
> appropriately
> >>>     be represented as numerical values" and that it "glosses over
> >>>     inconsistencies - beliefs may be logically incompatible".  I was
> >>>     intrigued by the suggestion, can you say more?
> >>>
> >>>
> >>>     Again, thanks all for a stimulating telecon on Wednesday.
> Apologies
> >>>     in advance if this address is not the right forum for these
> >>>     discussions.
> >>>
> >>>     Best regards,
> >>>
> >>>     Mike Pool
> >>>
> >>>     --------------------------------
> >>>
> >>>
> >>>
> >>> ----------------------------------------------------------------------
> --
> >> -----
> >>> Ken Laskey
> >>> MITRE Corporation, M/S H305 phone: 703-983-7934
> >>> 7151 Colshire Drive fax: 703-983-1379
> >>> McLean VA 22102-7508
> >>>
> >
> >
> >
> 
> --
> 
> Ivan Herman, W3C Semantic Web Activity Lead
> URL: http://www.w3.org/People/Ivan/
> PGP Key: http://www.cwi.nl/%7Eivan/AboutMe/pgpkey.html
> FOAF: http://www.ivan-herman.net/foaf.rdf
Received on Monday, 16 July 2007 11:55:58 GMT

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