- From: patrick hayes <phayes@ai.uwf.edu>
- Date: Wed, 29 May 2002 13:32:59 -0500
- To: Brian McBride <bwm@hplb.hpl.hp.com>
- Cc: w3c-rdfcore-wg@w3.org
>Sans Chapeau > >At 10:39 24/05/2002 +0100, you wrote: >[...] > >>2. Can any URI ref be a property name or must there be some associated >>namespace? > >I'm concerned that this question is not quite capturing the issue. >As DaveB has pointed out, any URI ref can be associated with a namespace >using rdfs:isDefinedBy. > >I think there is consensus that there is no syntactic restriction on the >form of URI that can denote a property in the graph (though some graphs >may not be serializable in RDF/XML without some schema based trickery). > >M&S does, in my view, clearly say that a property must be "associated" with >a namespace. In answer to Pat's question, my interpretation of that, is that >M&S states it should be possible to determine what namespace is associated >with a property. OK, I guess. Suppose P is associated with one namespace in one graph and a different one in another graph, what happens if we merge the two graphs? > >We may choose to clarify those statements in M&S. > >I propose the following test case. > >Are the following two graphs, equal? > > <rdf:RDF xmlns:foo="http://example.org/b"> > <rdf:Description> > <foo:ar>foobar</foo:ar> > <rdf:Description> > </rdf:RDF> > >and > > <rdf:RDF xmlns:foo="http://example.org/ba"> > <rdf:Description> > <foo:r>foobar</foo:r> > <rdf:Description> > </rdf:RDF> > >Our present specs would say that they are. > >My reading of M&S is that it says that these two fragments of >RDF/XML do not represent the same information as they 'associate' >the uri http://example.org/bar with different namespaces. They do? Doesn't the xmlns: just specify a prefix to be used in interpreting the foo: notation in the document? Surely there isn't any implication that http://example.org/ba means anything at all by itself, is there (??) > >Thus a "clarification" is clearly in order. > >It seems that there a number of possible positions, including: > > 1) at least one of the above fragments of xml must be wrong, as the > same uri can't be 'associated' with two different namespaces > > 2) the above fragments of xml are "equal". (A different mechanism must be > used to determine the namespace associated with a URI.) > >Option 1 is closer to (my reading of) M&S. I think option 2 commands more >support in the WG and is I think, better. I agree. > >Propose: > > o The two graphs described in the above test case are equal > > o Resources which are RDF schema properties and classes MAY be described > in one or more associated schemas. > > Designers of RDF schemas SHOULD identify their schemas with a URI > reference which ends in a character which cannot be part of an XML > localname, such as "#" or "/". > > Designers of RDF schemas SHOULD identify the resources defined by > a schema with a URI consisting of the concatentation of the URI REF > of the schema with an XML localname. > > The resource identified by applying algorithm A (described below) to > URI U MAY contain RDF schema information about the resource identified > by U. > > The value of an isDefinedBy property of a resource MAY contain RDF > schema information about that resource. > >Algorithm A is the usual namespace splitting algorithm. > >The above need wordsmithing/refining, if the approach find favour with the WG. I like this. Pat -- --------------------------------------------------------------------- IHMC (850)434 8903 home 40 South Alcaniz St. (850)202 4416 office Pensacola, FL 32501 (850)202 4440 fax phayes@ai.uwf.edu http://www.coginst.uwf.edu/~phayes
Received on Wednesday, 29 May 2002 14:32:52 UTC