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Re: Feedback request

From: Graham Klyne <Graham.Klyne@MIMEsweeper.com>
Date: Fri, 01 Nov 2002 10:16:17 +0000
Message-Id: <>
To: pat hayes <phayes@ai.uwf.edu>
Cc: w3c-rdfcore-wg@w3.org

At 09:28 PM 10/31/02 -0600, pat hayes wrote:

>Quick request(s) for feedback. There are 5 parts to this message.
>Please say if you think that any of the following entailments should NOT 
>be valid in RDF or RDFS, or have any problems with the reasoning sketched. 
>Obviously "10" can be any string.
>1. (RDF)
>aaa ppp "10" .
>aaa ppp _:xxx .

According to the rationale that got us here (i.e. for tidiness), I think 
this MUST be valid.

>2. (RDF)
>aaa ppp "10"^^datatypefoo .
>aaa ppp _:xxx .


>3. (RDF)
>aaa ppp "10"@lang .
>aaa ppp _:xxx .


> From the above, and assuming bare literals denote themselves, then IR 
> must contain all bare literals (cuzof 1) and all values that any datatype 
> can map them into (cuzof 2) and maybe all pairs of all those things with 
> lang tags (not yet sure about that last one). So we might as well say 
> that IR contains all of LV, seems to me. In which case we would get

When you say "all pairs of things with lang tags", are to nrefering to that 
which denotes or that which is denoted?

>4. (RDFS)
>rdfs:Literal rdfs:subClassOf rdf:Resource .

rdfs:Literal being anything denoted by a literal?

>5. (RDFS)
>aaa rdf:type rdfs:Datatype .
>aaa rdfs:subClassOf rdfs:Literal .

That has rdfs:Literal containing all datatype values, or the union of all 
datatype value spaces?  (I think you said that before)  Seems OK to me.

So bare literals (lexical form) are rdfs:Literal values (because of self 
denotation), but I not sure that says anything about typed or 
language-paired literals.

>Terminology question: now we have lists, should the term 'container' be 
>understood to include lists as well as seqs, bags and alts? If so, does 
>anyone have an suggestion for a generic term for the older containers? 
>(Simple containers? Open containers? Bushy containers?)
>Can anyone fill in the blank for
>rdfs:comment rdfs:range ??? .

Ooooh! Interestring question.  If we agree that such comments are always 
presented as strings in the RDF source, then (following DanC) I suppose 
it's some class that contains xsd:string UNION <xsd:string,language-tag>.

(The caveat about strings:  do we allow a comment to be a URL pointing to a 
document?  I don't think so, BICBW.)

>Er..sorry, I ought to know this, but I am honestly unable to recall where 
>the hell we are now. Have we decided to NOT allow property datatyping, ie 
>the use of a datatype URI as a property to link a node to a bare literal, 
>with the datatype implication that the node denotes the resulting value? 
>Or to ALLOW it? That is, should
>aaa ppp "10"^^datatypefoo .
>aaa ppp _:xxx .
>_:xxx datatypefoo "10"
>or not? If so, how about the reverse entailment??

My understanding is that we're not specifiying it, but not prohibiting it.

I.E. somebody could define a set of datatype URIs that have both class 
extensions and property extensions to make that work, but we're not doing 
that here.

Again, I could be wrong.

This is just my sense of where we are, not strongly held views.


>Finally, here is my current take on the total RDF and RDFS namespaces. 
>Please correct any errors or omissions. In particular, did we trash 
>rdf:type   rdf:Property
>rdf:Statement rdf:subject rdf:predicate rdf:object
>rdf:Seq rdf:Bag rdf:Alt rdf:_1 rdf:_2 ...
>rdf:List rdf:first rdf:rest rdf:nil
>rdfs:domain rdfs:range rdfs:Resource rdfs:Literal rdfs:Class 
>rdfs:subClassOf rdfs:subPropertyOf rdfs:member rdfs:Datatype
>rdfs:seeAlso, rdfs:isDefinedBy, rdfs:comment  rdfs:label
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Graham Klyne
Received on Friday, 1 November 2002 11:42:33 UTC

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