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Re: Ensuring Assertions are identified

From: Shadi Abou-Zahra <shadi@w3.org>
Date: Thu, 19 May 2005 16:08:42 +0200
Message-ID: <428C9DEA.5080907@w3.org>
To: "public-wai-ert@w3.org" <public-wai-ert@w3.org>

Hi,

What are the arguments for or against each of the following approaches?


1. Sub classing External Vocabulary
Create EARL vocabulary that are subclasses of existing vocabulary. For example:

<rdfs:Class rdf:about="&earl;Person" rdfs:label="A human assertor">
  <rdfs:subClassOf rdf:resource="&foaf;Person"/>
</rdfs:Class>


2. Equality with External Vocabulary
Create EARL vocabulary and use OWL constraints to define equality with existing vocabulary. For example:

<rdfs:Class rdf:about="&earl;Person" rdfs:label="A human assertor">
  <owl:equivalentClass rdf:resource="&foaf;Person"/>
</rdfs:Class>

<rdfs:Class rdf:about="&earl;Person" rdfs:label="A human assertor">
  <owl:sameAs rdf:resource="&foaf;Person"/>
</rdfs:Class>


Regards,
  Shadi


Charles McCathieNevile wrote:
> 
> Hi folks,
> 
> it seems that there is nothing in OWL, RDFS or RDF that lets us enforce 
> a  constraint that an Assertion is identifiable.
> 
> We can find Assertions that don't have an identifier by using a SPARQL  
> query with the filter isBlank(). Then there is a question of how to 
> deal  with this.
> 
> It may be possible in OWL to say that the class of ValidAssertions is  
> disjoint with the class of things that can be found by a SPARQL query, 
> by  defining our own terms. We could also perhaps use the log:uri 
> property  developed by TimBL for CWM
> 
> [[
> uri
>     This allows one to look at the actual string of the URI which 
> identifies  this. (Cwm can get the URI of a resource or get the resource 
> from the  URI.) This is a level breaker, breaking the rule of not 
> looking inside a  URI. Use (eg with string:match) to replace RDF's old 
> "aboutEach"  functionality. Use to implement the URI spec and protocol 
> specs, etc.
> ]] - http://www.w3.org/2000/10/swap/doc/CwmBuiltins
> 
> I think that we should just suggest that doing this is a best practice,  
> and tools MAY provide a warning (for example something like the  
> interoperability analyser of Libby's that Jim pointed to last week.
> 
> cheers
> 
> Chaals
> 

-- 
Shadi Abou-Zahra,       Web Accessibility Specialist for Europe 
World Wide Web Consortium (W3C),             http://www.w3.org/ 
Web Accessibility Initiative (WAI),      http://www.w3.org/WAI/ 
IST WAI-TIES Project (WAI-TIES)     http://www.w3.org/WAI/TIES/ 
Evaluation and Repair Tools (ERT WG), http://www.w3.org/WAI/ER/ 
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Voice: +33(0)4 92 38 50 64             Fax: +33(0)4 92 38 78 22 
Received on Thursday, 19 May 2005 14:13:06 GMT

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