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

From: Antoine Zimmermann <antoine.zimmermann@emse.fr>
Date: Tue, 22 Oct 2013 09:47:12 +0200
Message-ID: <52662D80.2070701@emse.fr>
To: RDF WG <public-rdf-wg@w3.org>

I would like to stress that I brought to the Working Group the *very 
same* arguments against the change on datatype map.  None of these 
arguments have been considered important at the time, such that it was 
deemed purely editorial.
The current text is the result of a compromise that I can live with, but 
I still prefer, because of the arguments given below, to keep datatype 
maps as before (but I don't want to block the ref track process).

Here are links to the relevant discussions, to help solve the issue 

My review of Semantics, with the objection to the change:

See the rest of the thread (note that it includes discussion on union of 
graphs which is not relevant to the datatype issue).

Peter's reply wrt the datatype issue:

(and following emails)

There are also minutes of teleconferences containing discussions on this 
topic, where it is very clear that at least Pat, Peter, Sandro, Ivan and 
David consider the issue to be purely editorial, and so, not even worth 
a formal objection.

The main argument of the Working Group can be summarised with PFPS 
concise sentence:


in lists.w3.org/Archives/Public/public-rdf-wg/2013Jun/0134.html

And less bluntly:

"Datatype maps didn't get you anything.  They looked as if they provided 
an extra level of formality, but all that they did was require an extra 
level of magic.  Sure, this extra level of magic was generally benign, 
and invisible from users, but it certainly didn't match up with the way 
datatypes are defined in XML Schema datatypes the source of most of the 
usable RDF datatypes."

I do not agree with this statement but it has been the "official" answer 
to me at the time, and the arrangements in the text were sufficient for 
me to live with it, so I see no reason to use any other arguments in 
response to Michael, pointing to the relevant emails.


Le 22/10/2013 01:29, Michael Schneider a écrit :
> Dear RDF Working Group!
> This is my review of the Last-Call Working Draft of the
> "RDF 1.1 Semantics" specification.
> I like to repeat that I wasn't able to finish my review in the
> very short given time since the announcement of the LCWD
> as of 3 October, and that I have a strong stake on this document.
> As for my review of the "Concepts and Abstract Syntax" LCWD,
> I have created the review for the most-current Editor Draft,
> available at
>    <https://dvcs.w3.org/hg/rdf/raw-file/default/rdf-mt/index.html>
> In general, I am quite pleased with this document, even with most
> of the deliberate changes being made to the original RDF Semantics,
> and most of my comments are only about small details, and are not
> design-related (and can thus be, in principle, be dealt with later
> in the context of the upcoming CR). However, there is a single,
> design-related, issue which I consider urgent (as for to be
> treated in the context of the Last-Call phase), and important.
> * §7: The notion of a "datatype map" has been effectively
>    replaced by a new notion of "recognized IRIs". No further
>    explanation is being given for this change. I have to note
>    that the notion of datatype maps has been used and is
>    deeply integrated in several of the other core Semantic Web
>    specifications: SPARQL 1.1 (in the SPARQL Entailment
>    Regimes spec), OWL 2 (specifically in the RDF-Based Semantics),
>    and RIF (in the RDF-and-OWL Compatibility spec), and it is
>    probably generally in quite wide use, for example in many
>    scientific papers and books. I believe the notion of a
>    datatype map as very basic and relevant for the stack of
>    semantics specifications that are based on the RDF Semantics
>    spec. In addition, I have never encountered any bigger problem
>    with this notion, even though I have been highly involved with
>    it during the years, in particular in my work as the editor
>    of the OWL 2 RDF-Based Semantics. So under these circumstances,
>    I consider this change harmful for the foundation of the Semantic
>    Web, and with the lack of any rational the change even appears
>    to me to be an arbitrary choice. In my opinion, it goes too far
>    for a "1.1-style revision" of the RDF specification. In summary,
>    I cannot accept this change and ask the WG to bring back
>    the old notion of a datatype map.
> * §3: The chapter introduces the term "entailment regime",
>    but does not say much about it. As this term is also
>    introduced and quite intensively used in the SPARQL 1.1 spec
>    (in particular by the SPARQL Entailment Regimes spec), I
>    suggest to be a little more elaborate on the term, in order
>    to avoid that the terms are not understood differently in
>    the contexts of the two specifications.
> * §4, 2nd par: I would change the order of "referent and
>    denotion" to "denotion and reference" to match the order
>    of the two corresponding terms mentioned earlier in the text:
>    "denotes and refers to".
> * §5.3 (and for other entailment regimes as well): I suggest
>    to always be explicit on the entailment regimes, when it
>    comes to the terms "satisfies", "entails", etc. So it should
>    always be "simply entails", or "RDF entails", instead of only
>    "entails", even if this may be obvious from the context (it
>    probably isn't for everyone). After all, these are definitions
>    and should be as precise as possible.
> * §5.3: the "Technical Note" on not defining entailment
>    between graphs is in fact also a Change Note, and should
>    be marked as such in addition.
> * §5.4: The Simple-semantics theorem "Every graph is
>    satisfiable" is followed by the statement that "this
>    does not hold for extended notions of interpretation".
>    This text should be modified to say that it does not
>    _always_ hold for extended notions of interpretation.
>    One could still construct some extended notion where
>    it does hold, although not for any of the extended
>    notions in the RDF 1.1 Semantics.
> * §5.4, Technical Note: I recommend to remove the claim about
>    graphs containing many bnodes that this is "unlikely to
>    occur in practice". Actually, it is relatively common,
>    namely for OWL documents with many Boolean class expressions
>    when serialized in RDF, because for a union or intersection
>    class expression, the number of bnodes is proportional to the
>    number of classes occuring in the class expression.
>    Apart from this concrete case, an assumption of the given kind
>    has in my opinion no place in a spec document, specifically
>    not within a technical note.
> * §7, 1st par: typos:
>    - "... which datatype is identifier by..." should probably
>      say "identified"
>    - "... and should treat any literals type": probably
>      "typed literals"
> * §7, 2nd par: Why does the text not refer to the term
>    "lexical space", which is introduced in the RDF 1.1 Concepts
>    document and has been used in the original RDF Semantics
>    (and other standards as well)? In the given form, I see no
>    reason for the term's omission, and the text reads rather
>    awkward without a direct reference to the lexical space.
> * §7, 3rd par: "RDF processors are not REQUIRED". The word
>    "not" should also be written in uppercase to avoid
>    misconception while reading the text.
> * §8: Why is there no table presenting the "RDF Vocabulary"?
>    The RDFS chapter provides such a table, and the original
>    RDF Semantics did so as well. It would be useful, at least.
> * Appendices: Several of the appendix titles contain the text
>    "(Informative)", directly followed by the sentence
>    "This section is non-normative". This is redundant. I suggest
>    to remove "(Informative)" from the titles, in accordance
>    with the rest of the document.
> * Appendix D: I don't see a reason to repeat the "non-normative"
>    declaration for the appendix in each of its sub-sections.
> * Appendix D.2, vocabulary table: I suggest to add the additional
>    RDFS terms for the container vocabulary as well.
> * References: I do not understand why the following documents
>    are listed as "normative references":
>    - OWL2-SYNTAX
>   Best regards,
>   Michael Schneider

Antoine Zimmermann
ISCOD / LSTI - Institut Henri Fayol
École Nationale Supérieure des Mines de Saint-Étienne
158 cours Fauriel
42023 Saint-Étienne Cedex 2
Tél:+33(0)4 77 42 66 03
Fax:+33(0)4 77 42 66 66
Received on Tuesday, 22 October 2013 07:47:37 UTC

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