W3C home > Mailing lists > Public > w3c-rdfcore-wg@w3.org > January 2002

Re: review MT draft

From: Pat Hayes <phayes@ai.uwf.edu>
Date: Fri, 18 Jan 2002 19:12:46 -0600
Message-Id: <p05101024b86e76d0707f@[65.212.118.208]>
To: jos.deroo.jd@belgium.agfa.com
Cc: w3c-rdfcore-wg@w3.org
>  >>>>2/ my main comment is w.r.t. the need for unasserted triples
>>>>>i.e. one could assert e.g. rrr ppp ooo.
>>>>>suppose rrr is a resource which is a set of triples
>>>>>then those triples in rrr are *not* necesarily asserted
>>>>>OK, this is when ppp is something like log:implies
>>>>>or something else where we need dereferencing rrr
>>>>>(or rrr could be identified by value such as in N3)
>>>>>anyhow that rrr can be a set of unasserted RDF triples
>>>>
>>>>This point seems to go beyond RDF as it is currently constituted, so
>>>>unless we plan to open up this issue of resources being sets of
>>>>triples, I propose to ignore this issue for now.
>>>
>>>fair enough (for the current state of the art of RDF MT)
>>>but I think that "resources being sets of triples" are evident
>>
>>Well, of course a resource can be anything, so I guess it can be a
>>set; but saying that is one thing, and expecting to be able to get
>>inside the set and access its contents is something else. That is a
>>whole other issue that involves in effect adding a set theory to RDF.
>>It might be a simple set theory, but its still a big step from here
>>we are now.
>
>well, I thought that *set of triples* was an RDF graph...

True, true. Hmmm. And if we use a URI in a subject position that 
happens to be the URI of an RDF graph, then it seems reasonable 
enough that it ought to *denote* that set of triples, right? OK, I'm 
getting there...

>[[
>   An RDF graph can be defined in terms of labeled nodes and arcs
>   (see Appendix A), but we will use an equivalent but more convenient
>   definition, in which a graph is defined to be *a set of triples* of
>   the form <S, P, O>, where P is a URI reference (in the sense of
>   [RFC 2396]), which we will call auriref, S is either a uriref or a
>   blank node, and O is either a uriref, a blank node, or a literal.
>]]
>of course not necessarily asserted
>btw, I think the flag (asserted/unasserted) is at that set/graph level
>(and not at the individual triple level)
>also the (de)referencing is determined by ppp

Why ppp and not sss? [Later: Oh, I see, the ppp is what does the 
DEreferencing. Ah, cute. Some properties can look inside their 
subject/object denotations and get at the stuff inside. There are all 
kinds of semantic rocks lurking here, as Im sure you know, but we 
might be able to find a safe path through them.  More later...Sorry 
Im slow...]

Pat
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Received on Friday, 18 January 2002 20:12:50 EST

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