Pat Hayes wrote:
On Jun 30, 2010, at 11:50 AM, Nathan wrote:
Pat Hayes wrote:
On Jun 30, 2010, at 6:45 AM, Toby Inkster wrote:
On Wed, 30 Jun 2010 10:54:20 +0100
Dan Brickley <dan...@danbri.org> wrote:
That said, i'm sure sameAs and differentIndividual (or however it is
called) claims could probably make a mess, if added or removed...
You can create some pretty awesome messes even without OWL:
# An rdf:List that loops around...
<#mylist> a rdf:List ;
rdf:first <#Alice> ;
rdf:next <#mylist> .
# A looping, branching mess...
<#anotherlist> a rdf:List ;
rdf:first <#anotherlist> ;
rdf:next <#anotherlist> .
They might be messy, but they are *possible* structures using
pointers, which is what the RDF vocabulary describes. Its just about
impossible to guarantee that messes can't happen when all you are
doing is describing structures in an open-world setting. But I think
the cure is to stop thinking that possible-messes are a problem to be
solved. So, there is dung in the road. Walk round it.
Could we also apply that to the 'subjects as literals' general
discussion that's going on then?
For example I've heard people saying that it encourages bad 'linked
data' practise by using examples like { 'London' a x:Place } - whereas
I'd immediately counter with { x:London a 'Place' }.
Surely all of the subjects as literals arguments can be countered with
'walk round it', and further good practise could be aided by a few
simple notes on best practise for linked data etc.
I wholly agree. Allowing literals in subject position in RDF is a
no-brainer. (BTW, it would also immediately solve the 'bugs in the RDF
rules' problem.) These arguments against it are nonsensical. The REAL
argument against it is that it will mess up OWL-DL, or at any rate it
*might* mess up OWL-DL.
The Description Logic police are still in charge:-)
As you know I'm pretty new to this, relatively, but here's a thought I
can't get rid of.
Keep RDF as loose as possible at the core semantic level (subjects as
literals etc).
Have the semantics of each triple defined by it's predicate (each
property can define it's own domain and range etc)
This may also allow for using rdf as a data model, and there's no reason
every triple must be dereferencable etc.
Above this, afaict, no reason why each serialization can't have it's own
strong semantics too, like HTML+RDFa can instruct that a URI should be
embedded and so forth (<img src=).
Just a thought.. I'm sure you can tell me why I'm wrong
re OWL DL, does it have to consider every triple in a 'graph'?
Nathan