W3C home > Mailing lists > Public > w3c-rdfcore-wg@w3.org > June 2001

Re: draft partitioning of the issues

From: pat hayes <phayes@ai.uwf.edu>
Date: Mon, 25 Jun 2001 17:04:46 -0500
Message-Id: <v04210114b75d64bf3779@[205.160.76.188]>
To: Aaron Swartz <me@aaronsw.com>
Cc: w3c-rdfcore-wg@w3.org
>On Sunday, June 24, 2001, at 09:25  AM, Brian McBride wrote:
>
>>>I also believe the following issues are in scope for the Working Group:
>>>
>>>rdfms-literals-as-resources and rdfms-literalsubjects:
>>>A large body of implementation and user experience shows the need 
>>>for these issues to be clarified. I think that there is certainly 
>>>room for clarification of this within the charter of the Working 
>>>Group.
>>
>>I'm a bit confused by this one Aaron.  Whilst I'm not arguing (yet) whether
>>these are in or out of scope, they don't seem to be about clarification.
>>Is there any doubt that as far as m&s is concerned:
>>
>> o literals are not allowed as subjects
>> o literals are not resources
>
>I do not see either of these stated in the spec. M&S says:
>
>	 pred is a property (member of Properties), sub is a resource
>	(member of Resources), and obj is either a resource or a
>	literal (member of Literals).
>
>but it never says that literals and resources are disjoint in any 
>normative portion of the document (to my knowledge, after a quick 
>search).

Right. And I thought that 'resource' meant the same as 'entity', and 
therefore a literal would be a resource. In fact everything is a 
resource. (If this is false, can anyone point me at a definition of 
'resource' which explains how to distinguish non-resources?)

>
>>Which is maybe not how some folks would like it to be.  If we considered
>>introducing this change, do you think we would need a syntax change to
>>represent it?  Of course, anyone can now use data uri's now if they want to.
>>We don't have to do anything to support that.
>
>No, I do not think a syntax change is necessary. This is simply a 
>change to the abstract syntax.

?? Surely a change to the abstract syntax is likely to require a 
change in any concrete syntax ??

>
>>>rdf-equivalent-uri's:
>>>Experience with the DAML specification has shown equivalence
>>>to be a useful and perhaps even essential property. It's absence from the
>>>schema spec is, in my opinion, an error.
>>
>>I try to avoid using words like 'error', but I have long felt that such
>>a facility would be useful.  I remember Mike Dean commenting at the
>>Boston f2f that equivalence was "something that should get implemented
>>early".
>
>Yes, apologies if I offended anyone with the term error. However, I 
>feel strongly that this is a useful facility.

I agree. However, equivalence usually means 'having the same 
referent' or '....same denotation'. So unless we have the notion of 
whatURI's denote reasonably clear, we probably won't be able to get 
equivalence clear; and if we do, it will be semantically trivial.

Pat Hayes

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Received on Monday, 25 June 2001 18:04:47 EDT

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