Re: Handling multiple rdfs:ranges

On Mon, Feb 29, 2016, at 03:04, David Booth wrote:
> On 02/26/2016 06:04 AM, Reto Gmür wrote:
> > Sure, still I think that schema:rangeIncludes is not meaningless (as it
> > restricts the rdfs:range statements that are possible) and that
> 
> Under the standard open world assumption (OWA) I do not think it is 
> correct to say schema:rangeIncludes *restricts* anything.  Bear in mind 
> that given the statement:
> 
>    :p schema:rangeIncludes :Cat .
> 
> one could always add an arbitrary additional class to the property's 
> "expected type(s)" by adding another statement like:
> 
>   :p schema:rangeIncludes :Dog .
> 
> Therefore, the original statement cannot be *restricting* anything 
> (under the OWA).

I did not say that it restricts the possible values of the properties,
but I'm saying that it restricts the possible rdfs:range statements that
are possible without creating a contradiction.

> 
> Personally, I think a reasonable way to interpret its meaning is that it 
> says 'there exists an individual :d such that :d rdf:type :Dog'.
> 
> > it has
> > some pragmatic usefulness such as when building editors that suggest
> > values for a specific property.
> 
> Agreed.  And it's also useful if you're doing closed world reasoning.

Well, even if you're closing the world I'm not sure you can do reasoning
about the instance data based on this property.

I claim that for something to be expected it must be possible, based on
this one can create a contradiction with statements of necessity
expressed with rdfs:range.

However, I don't think that only what is expected is possible. So even
if we know that only :Cat and :Dog are expected the unexpected :Mouse is
still possible.

Reto

Received on Monday, 29 February 2016 08:51:23 UTC