Re: OWL 2 Struct. Spec specification problem? - "absolute IRI"

Thanks for the suggestion. As you may have seen, adding a  
parenthetical disambiguation "(i.e., not relative)" proved  
satisfactory for the commenter (Daniel Barclay); hopefully it is OK  
for you too :-)

Ian


On 31 Aug 2009, at 19:28, Michael Schneider wrote:

> Hi WG!
>
> According to RFC 3987, Section 2.2, the ABNF for the non-terminal  
> "IRI" is
> given by (after some non-terminal substitution not made in the spec  
> but by
> myself):
>
>      IRI ::= absolute-IRI [ "#" ifragment ]
>
> So it seems reasonable to me to only do a very small change to the
> Structural Spec of the form:
>
>    Each IRI MUST be absolute
>    with an optional fragment.
>
> Btw, the RDF-Based Semantics has this as a topic as well:
>
>
> <http://www.w3.org/2007/OWL/wiki/RDF-Based_Semantics#topic-ont- 
> noteiriref>
>
> Michael
>
> From: public-owl-comments-request@w3.org
> [mailto:public-owl-comments-request@w3.org] On Behalf Of Barclay,  
> Daniel
> Sent: Monday, August 31, 2009 7:59 PM
> To: public-owl-comments@w3.org
> Subject: OWL 2 Struct. Spec specification problem? - "absolute IRI"
>
> In the OWL 2 Web Ontology Language Structural Specification and
> Functional-Style Syntax draft at
> http://www.w3org/TR/2009/CR-owl2-syntax-20090611/, section 2.4, IRIs,
> says:
>
>    Ontologies and their elements are identified using  
> Internationalized
>    Resource Identifiers (IRIs) [RFC3987]; thus, OWL 2 extends OWL 1,
>    which uses Uniform Resource Identifiers (URIs).  Each IRI MUST be
>    absolute.
>
> That wording probably should be adjusted so that readers don't
> accidentally assume that those IRIs must be absolute in the sense in
> which RFC 3986 uses the term (that is, not having fragment  
> identifiers).
>
>
> That OWL specification is based on RFC 3987, and RFC 3987 is based
> on RFC 3986.
>
> Unfortunately, RFC 3968 doesn't use "absolute" in the normal sense
> (meaning not relative to something); it uses "absolute" to refer to  
> not
> having a fragment identifier.
>
> Its section 4.3 (see http://tools.ietforg/html/rfc3986#section-4.3)
> says:
>
>    4.3. Absolute URI
>
>      Some protocol elements allow only the absolute form of a
>      URI without a fragment identifier.  For example, defining
>      a base URI for later use by relative references calls for
>      an absolute-URI syntax rule that does not allow a fragment.
>
>          absolute-URI  = scheme ":" hier-part [ "?" query ]
>
>       ...
>
> Although that first sentence could be explained as first referring to
> URIs that are absolute in the usual sense and then only referring
> to the subset of those without fragments, it easily sounds like it's
> defining "absolute" to mean not having a fragment component.
>
> Regardless of that first sentence, the name of the absolute-URI
> production strongly implies that "absolute URI" refers to the strings
> matching that production.  Given the lack of anything saying that
> the English phrase "absolute URI" does not in fact refer to what the
> absolute-URI grammar production generates, the only reasonable
> interpretation is that RFC 3986 defines "absolute URI" to refer to
> URIs without fragment components.
>
> Since allowing only non-fragment IRIs is _not_ what the OWL
> specification means to specify (right?), the OWL spec.'s text should
> also refer to not being relative or not being an IRI reference (or
> should refer to allowing fragment portions) to be clear.
>
>
> Daniel
> --
> (Plain text sometimes corrupted to HTML "courtesy" of Microsoft  
> Exchange.)
> [F]
>
> --
> Dipl.-Inform. Michael Schneider
> Research Scientist, Dept. Information Process Engineering (IPE)
> Tel  : +49-721-9654-726
> Fax  : +49-721-9654-727
> Email: michael.schneider@fzi.de
> WWW  : http://www.fzi.de/michael.schneider
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>

Received on Friday, 4 September 2009 08:25:08 UTC