- From: Dave Reynolds <dave@epimorphics.com>
- Date: Fri, 31 Aug 2012 14:43:33 +0100
- To: Semantic Web <semantic-web@w3.org>
- CC: Stuart Williams <skw@epimorphics.com>
On 31/08/12 14:25, Bernard Vatant wrote: > Stuart Williams in cc who is not subscribed to this list gave me the > green light to forward his thoughts, copied below. > In answer to the last remark about the ontology and ontology document > distinction, Dave Reynolds pointed to the OWL 2 specification > http://www.w3.org/TR/owl2-syntax/#Ontology_IRI_and_Version_IRI > > As Stuart, I'm not sure this specification totally clarifies the > ontological status of an ontology. As written before, using FRBR to make > distinct the ontology as an abstract work and its various expressions > and manifestations seems the way to get out of those misty territories. Actually I pointed to the next section [1] which I think is entirely clear that there is one URI. It may leave the ontological status open but it closes the practical status. You use the same URI to: o identify the Ontology via <OI> rdf:type owl:Ontology . o reference an ontology via owl:imports <OI> o fetch the ontology document, whether in a browser or in code like Bernard's harvester *If* you believe there is a distinction between the Ontology and the Ontology Document and *if* you want to make statements specifically about the Ontology Document then you are free to mint a separate URI for it (whether introduced via 303s or via rdfs:isDefinedBy) but as far as OWL is concerned one URI is necessary and sufficient. Dave [1] http://www.w3.org/TR/owl2-syntax/#Ontology_Documents > ----------------------------- > Stuart Williams wrote : > > FWIW I think that there are two consistent views and two sets of > associated URI patterns. > > View 1: An Ontology and the document resource(s) that describe it are > different things and therefore need different URIs. > ------ > For so-called "#-ontologies": > Namespace Prefix: http://{authority}/{vocabulary-path}# > Base URI: http://{authority}/{vocabulary-path} > > Ontology Document generic URI: http://{authority}/{vocabulary-path} > Ontology URI: http://{authority}/{vocabulary-path}# > > Base relative terms references #{term} (but beware of > same-document references RFC 3996 section 4.4) > > For so-called "/-ontologies": > Namespace Prefix: http://{authority}/{vocabulary-path}/ > Base URI: http://{authority}/{vocabulary-path}/ > > Ontology Document generic URI: http://{authority}/{vocabulary-path} > Ontology URI: http://{authority}/{vocabulary-path}/ > > Base relative terms references {term} > > In both cases the namespace URI (which as a namespace has no > significance - it's just a device to abbreviate a URI) and Ontology URI > are identical. > The base URI for #-ontologies matches the ontology document (to make > relative referencing useful) and for /-ontologies matches the ontology > itself (again to make relative referencing useful). > > View 2: An owl serialisation is merely a representation of an > Ontology... there is only one (generic) resource here (and its ttl, nt, > rdf etc. variants) > ------ ie. the document and the ontology are one and the same thing. > > For so-called "#-ontologies": > Namespace Prefix: http://{authority}/{vocabulary-path}# > Base URI: http://{authority}/{vocabulary-path} > > Ontology Document generic URI: http://{authority}/{vocabulary-path} > Ontology URI: http://{authority}/{vocabulary-path} > > Base relative terms references #{term} > > For so-called "/-ontologies": > Namespace Prefix: http://{authority}/{vocabulary-path}/ > Base URI: http://{authority}/{vocabulary-path}/ [1] > http://{authority}/{vocabulary-path} [2] > > Ontology Document generic URI: http://{authority}/{vocabulary-path} > Ontology URI: http://{authority}/{vocabulary-path} > > Base relative terms references {term} [1] > ./{term} [2] > > For the '/-namespace' there is a tension between whether to match the > base URI with the natural ontology/document URI which makes for slightly > more awkward relative referencing match it with the namespace name which > makes for more 'natural' relative referencing. > > In either view it is the ontology and document (if you take the position > of them being different things) identifiers that are crucuially > important. The base URI and namespace URI are just devices for URI > shortening and that can be got right (even if not always at first > attempt - folks can miss that resolving relative references is not > simple concatenation). > > For myself - I have never been quite able to commit (universally) to an > ontology and its describing document being the same thing. I'm open to > the possibility... but I haven't found anything in the OWL documents > that resolves that for me (maybe haven't look hard enough). So I tend to > be a view #1 /-ontologies sort of a person - misguided though I may be :-). > > ------------------------------ >
Received on Friday, 31 August 2012 13:44:15 UTC