Re: Comments on Last-Call Working Draft of RDF 1.1 Semantics

On 12/11/2013 07:52 AM, Antoine Zimmermann wrote:
> Le 10/12/2013 09:22, Pat Hayes a écrit :
>>
>> On Dec 9, 2013, at 9:12 PM, Pat Hayes <phayes@ihmc.us> wrote:
>>
>>> On Dec 9, 2013, at 4:15 PM, Michael Schneider <schneid@fzi.de>
>>> wrote:
>> ....
>>>
>>>> There will be no further involvement into the discussion from my
>>>> side, except for answering concrete requests, e.g. for
>>>> clarification, etc. It's now up to the WG to make a decision.
>>>> What I can say is that if this change makes it into PR, I'm going
>>>> to formally object, and my basic line of argumentation should be
>>>> clear by now.
>>>
>>> It is not clear to me. As the change does not affect any
>>> entailments and does not alter the actual interpretation structures
>>> being described, and as the documents now (in reponse to your
>>> original comment) exactly define the 2004 notion of datatype map so
>>> as to provide backwards compatibility with earlier specifications
>>> which use the concept, I do not see what the basis is for your
>>> objection, other than that you prefer the older style of
>>> exposition.
>>>
>>
>> Let me slightly modify my stance here. Since writing this I have
>> taken a careful look at the 2010 OWL 2 RDF specification you edited,
>> and I see that you there make very detailed reference to much of the
>> formal machinery defined in the 2004 RDF Semantics document,
>> repeating and then modifying or extending many of the exact
>> definitions, including those of datatype maps. In order to refer to
>> the RDF 1.1 Semantics rather than the 2004 Semantics in the same way
>> would require, I now see, extensive editorial changes to the 2010 OWL
>> 2 RDF document, since many of those definitions have now been
>> modified or in some cases removed from the RDF 1.1 Semantics
>> altogether. However, the particular issue we are discussing here
>> seems to be only one of these changes, and not one that affects any
>> entailments in either RDF or OWL 2. It would be straighforward, if
>> tedious, to re-word the relevant sections (chiefly 4.1 and 4.2, with
>> minor wording changes in 3.3 and 3.4) so that they used the concepts
>> of D-interpretation and recognized IRIs defined in the RDF 1.1
>> Semantics document, rather than referring to the datatype map
>> construct used in the 2004 RDF specifications, while still describing
>> exactly the same extended semantic structures related to RDF in the
>> same way. (Other differences between the 2004 and 2013 RDF semantics
>> descriptions seem to have more far-reaching editorial consequences;
>> for example, that intepretations in RDF 1.1 are not defined with
>> respect to a vocabulary. Others require changes to actual
>> entailments, in particular the fact that ill-formed literals produce
>> inconsistencies in RDF without using the RDFS extension.)
>>
>> Nevertheless, in order to make the connection to the 2004 definitions
>> more explicit, let me suggest that we change our wording by adding to
>> the end of the first paragraph of section 7 so that it reads as
>> follows:
>>
>> -----
>>
>> Datatypes are identified by IRIs. Interpretations will vary according
>> to which IRIs they recognize as denoting datatypes. We describe this
>> using a parameter D on simple interpretations. where D is the set of
>> recognized datatype IRIs. We assume that a recognized IRI identifies
>> a unique datatype wherever it occurs, and the semantics requires that
>> it refers to this identified datatype. The exact mechanism by which
>> an IRI identifies a datatype IRI is considered to be external to the
>> semantics, but we may describe this identification as a mapping from
>> recognized IRIs to datatypes, called a <def>datatype map</def>.
>>
>> and then modify the change note as follows:
>>
>> <Change note> In the 2004 Semantics specification, D was defined to
>> be a datatype map rather than a set of IRIs.  This  permitted
>> "non-standard" datatype maps which map IRIs to datatypes they do not
>> identify (such as one that maps the IRI
>> 'http://www.w3.org/2001/XMLSchema#decimal' to the datatype identified
>> by http://www.w3.org/2001/XMLSchema#gYearMonth ). Semantic extensions
>> based on such non-standard mappings are not sanctioned by this
>> specification.
>
>
> Leaving aside the rest of the proposal for the moment, this change 
> note must not appear in the spec. Having datatype maps or sets does 
> not make any difference wrt this issue, and in any case, 
> "pathological" datatype maps were ruled out of the definition long 
> before an Editor's draft of Semantics even existed. 

Are you saying they were ruled out in the 2004 spec?   I'm looking at 
http://www.w3.org/TR/rdf-mt/#DTYPEINTERP and I don't see something like 
that.

> See RDF 1.1 Concepts WD in June 2012, revised in January 2013, and the 
> ED still contained the definition until May 2013.
>

(I'm confused how those might be relevant.)

> It has been your most repeated argument against datatype map, but it 
> is falacious.
>

The argument I hear Pat making against datatype maps is that they are an 
unnecessary complication, one more variable than we actually need.   
That's the argument that resonates with me, although I don't claim to 
understand all facets of this matter.

          -- Sandro

>
> AZ.
>
>>
>> --------
>>
>> I believe this establishes sufficient connection between the 2004
>> 'datatype map' terminology and the 2013 'recognized IRI' terminology
>> to enable conditions stated in the 2004 language to apply clearly to
>> the 2013 specifications. Do you agree?
>>
>> Pat
>>
>>
>
>

Received on Wednesday, 11 December 2013 13:38:06 UTC