Re: making statements about the lexical form of a URI

On Fri, Aug 13, 2010 at 12:52 AM, Nathan <nathan@webr3.org> wrote:

> David Booth wrote:
>
>> On Thu, 2010-08-12 at 21:57 +0100, Dave Reynolds wrote:
>> [ . . . ]
>>
>>>   "http://xmlns.com/foaf/0.1/name" a foo:URI;
>>>>       foo:uriLength 30;
>>>>       foo:uriAuthorityHost "xmlns.com";
>>>>       foo:xxxxx <http://xmlns.com/foaf/0.1/name>;
>>>>
>>>> The specific question is, how do you unambiguously identify a URI in
>>>> order to make statements about the lexical form of that URI?
>>>>
>>> In OWL full the domain of owl:Thing is the whole universe of discourse,
>>> including literals. So I believe in OWL Full you can equate a individual
>>> with a literal and then describe properties of that individual:
>>>
>>>  [] owl:sameAs "http://xmlns.com/foaf/0.1/name"^^xsd:anyURI;
>>>     foo:uriLength 30;      foo:uriAuthorityHost "xmlns.com" .
>>>
>>
there seems to be a misunderstanding here.

>
>>> Using a blank node rather than a URI is not necessary but is clearer.
>>
>> . . . except of course that it *is* necessary at present, because at
>> present RDF does not permit literals as subjects.
>>
>
> Thanks, saved me saying that one :)
>
Instead of using a bnode you could use nay URIRef, which would name the
literal value. The UriRef used as name for the literal uri need not have any
relation to it.

>
> also, with regards owl:sameAs - given my example at the top, how would one
> specify: (associate the literal with the uri)
>
>  <http://xmlns.com/foaf/0.1/name> owl:sameAs "
> http://xmlns.com/foaf/0.1/name"^^xsd:anyURI .
>
> given that
>  <http://xmlns.com/foaf/0.1/name> owl:sameAs <http://ex.org/blah> .
>
> and
>  <http://ex.org/blah> owl:sameAs "http://ex.org/blah"^^xsd:anyURI.
>
> because the above triples would imply all kinds of Falsehoods
>
The graph with these three triples expresses a contradiction, it is false in
every possible world, but there's nothing wrong with that ;)

Reto

>
>