- From: Bijan Parsia <bparsia@isr.umd.edu>
- Date: Sun, 21 Nov 2004 10:22:14 +0900
- To: Ian Dickinson <ian.dickinson@hp.com>
- Cc: public-sws-ig@w3.org
On Nov 21, 2004, at 9:26 AM, Ian Dickinson wrote:
> Daniel Elenius wrote:
>> [snip]
>> And also
>> ds:ClosedList a owl:Class
>> ; rdfs:subClassOf ds:List .
>> right?
> 'Fraid not. The first/rest/nil construct already gives you a closed
> list.
Doesn't stop it from being a subclass, of course :)
Alas, first/rest/nil doesn't quite do the job without an "aware"
processor.
> The most common way to do a bag-like construct in OWL/RDF is to use a
> repeated property, but this has the drawback (some say, others
> disagree) that under the standard open-world assumption, you never
> know how many values there are:
No. Just add a restriction (or use a oneOf).
> ex:foo
> a ex:Bar
> ; ex:hasArg "1"
> ; ex:hasArg "2"
> .
>
> How large is the bag of arguments of foo? Answer: no less than 2.
Well, in this case, only because of builtin he inequality of the
literals.
> If, however, you encode the args as a list, it's a closed construct
> and you know exactly the size of the list (or bag, if you mean to
> interpret it that way).
ex:foo a Restriction onProperty ex:hasArg cardinality = 2.
Now you know :)
Alternatively (but nastier).
fooargs oneOf {:a :b}. :a differentFrom :b.
ex:foo a Restrictin nProperty ex:hasArg allvaluesfrm fooArgs.
That only gives you a maxcardinality, natch.
Personally, I strongly feel that using lists like that is way way way
way worse style. It doesn't really give you want you want, and in most
cases it's not necessary.
[snip]
> If that's an important distinction to be made, then yes. I'm simply
> advocating that the distinction not be made solely by parsing the name
> of the class. URI's are supposed to be opaque :-)
It's not made by *parsing* the URI. We use two URIs to indicate two
(possibly) distininct concepts and use simple URI comparison to
determine which concept we're dealing with (although a vanilla owl
reasoner can't determine that they are distinct).
Cheers,
Bijan Parsia.
Received on Sunday, 21 November 2004 01:22:25 UTC