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D-entailment question in http://www.w3.org/TR/2014/PR-rdf11-mt-20140109/

From: Axel Polleres <axel.polleres@wu.ac.at>
Date: Tue, 28 Jan 2014 08:53:41 +0100
Message-Id: <7F64D5FE-AC05-4BD2-B3E4-8929B3003590@wu.ac.at>
To: public-rdf-comments@w3.org
Dear RDF 1.1 WG,

First of all let me thank the WG for their efforts and work on gettin the new RDF1.1 spec to PR.
My new affilation organization (WU Wien) has recently joined W3C and I have started looking 
in a bit more detail into the new specs.

When looking over the definition of D-entailment, and also related comments on the list, I have some small question:

If I see it correctly, and that’s good news, D-entailment is no longer stacked on top of RDFS Entailment. I very much welcome this change.
Next, I wonder only about one thing regarding the removal of datatype maps. As I understand the discussions, the intention here is 
to simplify things, by assuming that known IRIs *identify* datatypes, i.e. there is a fixed interpretation for such known IRIs, 
and that this fixed interpretation of a datatype IRI aaa is associated with a known lexical-to-value mapping L2V.

However, Section 7.1 seems to have no pointers to a *definition* of what is a *datatype* or a *lexical-to-value* actually is, nor give any information of how a custom datatype is defined, e.g. 

"For every other IRI aaa in D, I(aaa) is the datatype identified by aaa, and for every literal "sss"^^aaa, IL("sss"^^aaa) = L2V(I(aaa))(sss)”

seems to miss that L2V is the associated lexical-to-value mapping for I(aaa).

Also, I find the remote definition of *identify* in section 4 ("when we wish to refer to such an externally defined naming relationship, we will use the word identify and its cognates.”)
insufficient to give a proper definition to what a datatype is.

I would kindly ask the group for two things:
a) to add more explanatory text or pointers to other specs to make these definitions more self-contained.
b) explain, even if only in an informal section, how custom datatypes should be defined (which several existing RDF datasets do)

If I understand this correctly, such informal addition as well as adding explaining text or references to other specs containing the resp. definitions 
would not be a substantial change, and not affect PR status.

best regards,

Prof. Dr. Axel Polleres
Institute for Information Business, WU Vienna
url: http://www.polleres.net/  twitter: @AxelPolleres
Received on Tuesday, 28 January 2014 07:54:07 UTC

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