- From: Pat Hayes <phayes@ihmc.us>
- Date: Thu, 12 Dec 2013 01:16:22 -0800
- To: RDF WG <public-rdf-wg@w3.org>
- Cc: Michael Schneider <schneid@fzi.de>, Antoine Zimmermann <antoine.zimmermann@emse.fr>
I propose the following changes to section 7 of the semantics document, in reponse to the critical comments from Michael Schneider. No changes are required to Concepts. As time is short, if anyone other than Michael or Antoine objects to this, please speak up ASAP, thanks, or just revert the changes yourself in Mercurial. The changed text has just been pushed into Mercurial in respec format, but Im not sure if it is publicly viewable there. As this does not materially change the way the semantics is currently written, and in particular it does not revert wholesale to the 2004 style of description in the way that Antoine has suggested, I doubt if it will satisfy Michael or Antoine, but I believe it serves to effectively establish backward compatibility with other specifications which refer to the 2004 concept of datatype maps. --------- Section 7 Datatypes are <a title="identify">identified</a> by IRIs. Interpretations will vary according to which IRIs are recognized as denoting datatypes. We describe this using a parameter D on simple interpretations. where D is the set of <def>recognized</def> datatype IRIs. <p class="change note"> The previous version of this specification defined the parameter D as a <a>datatype map</a> from IRIs to datatypes, i.e. as a restricted kind of interpretation mapping. As the current semantics presumes that a recognized IRI identifies a unique datatype, this IRI-to-datatype mapping is globally unique and externally specified, so we can freely abuse notation by thinking of D as either a set of IRIs or as a fixed datatype map. Formally, the <def>datatype map</def> corresponding to the set D is the restriction of a D-interpretation to the set D. Semantic extensions which are stated in terms of conditions on datatype maps can be interpreted as applying to this mapping.</p> The exact mechanism by which an IRI identifies a datatype IRI is considered to be external to the semantics, but the semantics presumes that a recognized IRI identifies a unique datatype wherever it occurs. RDF processors which are not able to determine which datatype is identified by an IRI cannot recognize that IRI, and should treat any literals with that IRI as their datatype IRI as unknown names. [[Remove the second 'change note']] ------ Two paragraphs later, add a [[sentence]] to the end of the paragraph: .... RDF processors may recognize other datatype IRIs, but when other datatype IRIs are recognized, the mapping between a recognized IRI and the datatype it refers to must be specified unambiguously, and must be fixed during all RDF transformations or manipulations. [[In practice, this can be achieved by the IRI linking to an external specification of the datatype which describes both the components of the datatype itself and the fact that IRI identifies the datatype, thereby fixing a value of the <a>datatype map</a> of this IRI.]] ------ I have removed the material about "irrational" datatype maps, which is contentious and is probably only a distraction in the current semantics in any case. I also followed Antoine's suggestion to change "fail to recognize" to "do not recognize" in a later paragraph. Pat ------------------------------------------------------------ IHMC (850)434 8903 home 40 South Alcaniz St. (850)202 4416 office Pensacola (850)202 4440 fax FL 32502 (850)291 0667 mobile (preferred) phayes@ihmc.us http://www.ihmc.us/users/phayes
Received on Thursday, 12 December 2013 09:16:53 UTC