RE: wildcard resource representation

Hi Garret,

GW:
>I'm creating an ontology in which it is useful to identify "any 
>resource". That is, let's say that I want to specify to which resource a 
>particular <eg:Rule> applies. I can specify (let me try my hand at N3
here);

[...]

>If I assume that the resources are people with emails, I could use
><mailto:*.*>. But that doesn't seem general enough---it's almost
>too much of a hack.

If I understand you correctly you want to say something like: if there is an
resource ?A such that there is a triple (?A, foaf:mbox,?B) then there is a
triple (eg:Rule,eg:applies,?A) ... you want to make statements about a
subset of resources for which some condition holds ...  I'ld use rules to
represent that, for example with Jena' general purpose rule engine [1] you
write this as:

[Rule applies: (?A, foaf:mbox,?B) -> (eg:Rule,eg:applies,?A)

No "wildcards", but "variables" that help you achieve the same. 

For many cases you can achieve the same with OWL by defining a class of all
the resources you're interested, e.g. 
foaf:mbox rdf:type owl:ObjectProperty;
          rdfs:domain eg:PeopleWithEmail.
>From this an OWL reasoner should conclude that every resource A for which
there is a triple (A, foaf:mbox,*) is an instance of the class
PeopleWithEmail - abd then you can use this class to make statement about
your resources. 


[1]: http://jena.sourceforge.net/inference/#rules



cu

valentin

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-----Original Message-----
From: semantic-web-request@w3.org on behalf of Garret Wilson
Sent: Wed 8/1/2007 2:57 AM
To: Semantic Web
Subject: wildcard resource representation
 

Everyone,

I'm creating an ontology in which it is useful to identify "any 
resource". That is, let's say that I want to specify to which resource a 
particular <eg:Rule> applies. I can specify (let me try my hand at N3 here);

[] a eg:Rule;
  eg:appliesTo <urn:uuid:92f01109-e08e-4ac2-b0d4-b13f65ba7595>

That means that the rules applies to some identified resource. But is 
there any convention for identifying "any resource"? I see several options:

    * If I assume that the resources are people with emails, I could use
      <mailto:*.*>. But that doesn't seem general enough---it's almost
      too much of a hack.
    * Maybe there's a wildcard URI out there---that is, perhaps
      <urn:uuid:1234...> is universally agreed upon as the wildcard
      resource. But I'm not holding my breath that this exists.
    * Maybe I could create my own wildcard URI: <eg:wildcard>. But that
      seems too specific to my ontology.
    * What about a class of all resources? If I were to use
      <http://www.w3.org/2000/01/rdf-schema#Resource>, that doesn't seem
      to be what I'm wanting to say semantically---it would say that the
      rule applies to the class of resources, not to every instance of
      that class.
    * I could create a type <eg:AnyResource> and this could be the value
      of the eg:appliesTo property, but this seems to have the same
      problem as using the type <rdfs:Resource>.

Any suggestions? There are almost limitless ways I can go with this, but 
is there some convention?

Garret

Received on Wednesday, 1 August 2007 08:48:50 UTC