Re: partial response for LC comment 21 JDB2

From: "Michael Schneider" <schneid@fzi.de>
Subject: RE: partial response for LC comment 21 JDB2
Date: Tue, 3 Mar 2009 21:27:42 +0100

[...]

> However, the second point about different datatype maps is in my opinion an
> issue that needs discussion. For compatibility reasons, the notions of a
> datatype and a datatype map in the RDF-Based Semantics are inherited from
> the RDF Semantics spec ("D-entailment" = RDFS + datatype maps). In fact, the
> definitions there are used at several important places in the OWL 2 Full
> spec, and there are semantic conditions in D-entailment that need to be
> supported by OWL 2 Full as well. 
> 
> I have extended these notions of datatypes and datatype maps from the RDF
> Semantics conservatively in a way that they also support facets, and I have
> put quite a lot of effort into aligning the facet-related stuff to that in
> the Direct Semantics. This alignment has worked quite well so far. 
> 
> Nevertheless, this was merely an alignment of the main concepts (facet
> space, and the like). Structurally, the two definitions of a datatype map
> still differ significantly. For example, much of what is a part of a
> datatype in RDF (for example the lexical space) is actually assigned to that
> datatype by the datatype map in the Direct Semantics. In RDF, a datatype map
> is simply a mapping (hence the name) from datatype IRIs to the actual
> datatypes. In the Direct Semantics, a datatype map is a much more complex
> object. In RDF, all of that complexity is in the datatype itself.
> 
> I just want to note that in OWL 1 DL, the definition of a datatype map was
> pretty much the same as in RDF (at least structurally, of course without the
> additional semantic conditions of D-entailment). This has changed notably in
> OWL 2 DL, and I guess that Jos' comment targets this change. 
> 
> For the RDF-Based Semantics, I believe that I did all that what was possible
> for me to have as much compatibility between the two notions of an "OWL 2
> datatype map", without breaking compatibility with RDF. Conversion is easily
> possible now (I even demonstrate this at one place in the document), but the
> two notions are, after all, not the same.
> 
> Please read, with these considerations in mind, my proposed answers below.
> 
> Michael

I think that this change in presentation between the two semantics is
fine.  I also think that there really is not that much difference.

peter

Received on Wednesday, 4 March 2009 11:27:52 UTC