W3C home > Mailing lists > Public > www-rdf-interest@w3.org > December 2000

Re: Modelling a stating

From: Graham Klyne <GK@Dial.pipex.com>
Date: Sat, 09 Dec 2000 18:30:55 +0000
Message-Id: <4.3.2.7.2.20001209182010.00c8c100@pop.dial.pipex.com>
To: "McBride, Brian" <bwm@hplb.hpl.hp.com>
Cc: www-rdf-interest@w3c.org
At 05:11 PM 12/8/00 +0000, McBride, Brian wrote:
>Pierre-Antoine,
>
> >   about 3.  I already submitted the idea below on the list,
> > but I will go further : the problem raised by Jonas is not a
> > problem ! If we do consider that the reified statement is
> > really a statement rather than a stating, then the date
> > should not be a property of st1, but rather of st2 and st4 !
> >
> >   st1: [Ora, creator, page]
> >   st2: [st1, saidBy, Ralph]
> >   st3: [st2, at, 01/12/99]
> >   st4: [st1, saidBy, Pierre-Antoine]
> >   st5: [st4, at, 01/12/00]
> >
> > The statements st2 and st4 are actually statings, not because
> > *every* reified statement be a stating, but because of the
> > particular meaning of their predicate "saidBy".
>
>Interesting approach.  I'm uncomfortable with st2 - you say its
>a model of a stating.  But its also, by definition a model of a
>statement.  I've been thinking that statements and statings are
>disjoint, so how can this be?  Are they disjoint?  Can the same
>thing model both a statement and a stating?

I see no reason why not (though the final answer may depend on the form of 
explanation (stating?) used -- so your call for formal language seems 
timely).  In the above, I think the line starting with 'st2:' is a 
description of a statement known as 'st2', which itself is an assertion of 
a stating of the statement known as 'st1'.

>We need some more formal language here - its too confusing
>otherwise.
>
>What's key about the concept of a
>stating?  Basically, its a multi-valued relation - e.g.
>
>(stating, stmt, location, by, time, weather-conditions,...)
>
>or in predicate terms:
>
>   stating(stmt, location, by, time, weather-conditions, ...)
>
>In RDF we only have binary predicates, so this becomes
>
>   type(x, stating)
>& stmt(x, ...)
>& location(x, ...)
>& by(x, ...)
>& time(x, ...)
>& weather-conditions(x, ...)
>& ...
>
>Can we deduce this from st1, st2, ...?  Are there a set of axioms
>that would enable that deduction.  And is it worth the computation
>over representing things more directly?

To answer the first question, I think the answer should be "yes".

As to the second, I would say that implementers are free to choose an 
internal representation that suits their computational needs.  For the time 
being, RDF is our assumed form of interchange and I don't feel it's 
productive to consider alternatives at this time if RDF is adequate.  But 
if RDF is broken...

--

I like the approach you take above above... it puts me in mind of the idea 
the a reification quad is the _minimum_ needed for a structure to qualify 
as a description of a statement, and arbitrary additional details may be 
added to create a richer description of the statement.  I think this tends 
to loosen the identity between reification quad and statement, while 
retaining the essential elements.

#g

------------
Graham Klyne
(GK@ACM.ORG)
Received on Sunday, 10 December 2000 10:20:46 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Monday, 7 December 2009 10:51:47 GMT