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

From: Guus Schreiber <guus.schreiber@vu.nl>
Date: Tue, 22 Oct 2013 10:37:08 +0200
Message-ID: <52663934.9000107@vu.nl>
To: Michael Schneider <schneid@fzi.de>, "public-rdf-comments@w3.org Comments" <public-rdf-comments@w3.org>
Dear Michael,

Thanks for your comment. We will be tracking these in two separate issues:

   ISSUE-165: datatype map

   ISSUE-166: non-urgent issues

We hope to be able to send responses soon.

Guus Schreiber
RDF WG co-chair

On 22-10-13 01:29, Michael Schneider wrote:
> 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
Received on Tuesday, 22 October 2013 08:37:43 UTC

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