Re: How does RDF get extended to new datatypes?

On Tue, Apr 30, 2013 at 12:58:19PM -0500, Pat Hayes wrote:
> > "http://example.org/daterange" is an IRI, not a datatype. So what datatype
> > does this system implements? Intuitively, this should mean that it
> > implements the datatype identified by "http://example.org/daterange". But
> > what this datatype is? It's not an XSD datatype, so the standards do not
> > say. There is no datatype map given, so my RDF-2004 assumptions do not
> > allow me to decide. Still, I have my Linked-data assumptions that tell me I
> > just have to look up and figure out. All right, let's do that. This URL is
> > redirecting to http://example.iana.org/, which does not tell me anything
> > useful.  So your entailment regime is incompletely defined.
> 
> True, in this case. But suppose we are following the 2004 spec, and we read
> some RDF which has a literal in it typed using this IRI. All we have is the
> IRI. How do we discover what datatype map is supposed to be used on this
> datatype? The spec provides no clue as to how to discover this. And what does
> it even *mean*? It means simply that we need to know what datatype this IRI
> is supposed to... well, to denote, in fact. That is, we have an IRI and we
> need to know what it is being used to denote, to refer to. That is exactly
> what the 2013 wording assumes: there is an IRI which evidently is being used
> to identify a datatype, and we are supposed to find out which datatype it
> refers to. (How to find out, is not specified: perhaps by using linked data
> principles, perhaps just by being inside the relevant user community.) But
> phrasing this as "finding out which datatype map it is being used with"
> doesn't add anything useful to the discussion. 

+1 for not raising the bar re: datatype IRIs

(That said, I'm unsure why "we need to know" or are "supposed to find out"
which datatype is denoted by an IRI.  Is it not an option to just ignore a
datatype?  If one simply doesn't know, does the data actually become invalid?)

Tom (who unfortunately cannot attend today's call - lunch with DanBri...)

-- 
Tom Baker <tom@tombaker.org>

Received on Wednesday, 1 May 2013 14:42:02 UTC