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Re: Comments on 17 December 2013 WD of RDF 1.1 Primer

From: Guus Schreiber <guus.schreiber@vu.nl>
Date: Mon, 3 Feb 2014 16:35:22 +0100
Message-ID: <52EFB73A.8060103@vu.nl>
To: Thomas Baker <tom@tombaker.org>
CC: RDF Working Group <public-rdf-wg@w3.org>, Public RDF comments list <public-rdf-comments@w3.org>
Tom, (cc: +public-rdf-comments@w3.org)

Thanks again for your comments. Responses inline.

On 08-01-14 05:19, Thomas Baker wrote:
> The Primer [1] is taking shape nicely!
>
> Bob DuCharme and Antoine Isaac have already raised alot of excellent points
> [2,3].  The comments below are divided into comments of substance, comments
> specifically about the NOTEs, and copyediting suggestions.
>
> I agree with Antoine that we should take the opportunity to help make it
> perfect...! :-)
>
> Tom
>
> [1] http://lists.w3.org/Archives/Public/public-rdf-comments/2013Dec/0124.html
> [2] https://dvcs.w3.org/hg/rdf/raw-file/default/rdf-primer/index.html#
> [3] http://lists.w3.org/Archives/Public/public-rdf-comments/2014Jan/0006.html
>
> ======================================================================
> Comments of substance
>
> --  "The Resource Description Framework (RDF) is a framework for describing
>      information about resources..."
>
>      This definition uses the same three words as what it defines -- Resource,
>      Description, and Framework.  How about:
>
>          The Resource Description Framework (RDF) is a language for expressing
>          information about things.

See also responses to Bob and Antoine. Changed as suggested except for 
"language". Admittedly, "framework" is a bit vague, but language would 
create the wrong expression (with so many concrete syntaxes floating 
around).

> --  "...about resources in the World Wide Web"
>
>      Do we want to project the message that RDF is really just about describing
>      Web pages and videos?
>
>      Paragraph three starts with "In particular, RDF can be used to publish and
>      interlink data on the Web" -- and IMO paragraph three is the right place to
>      make this connection.
>
>      I suggest dropping the second half of the first sentence and substituting
>      it with a sentence or two to the effect that RDF is a language for data
>      which uses Web addresses as globally defined names for things and leverages
>      those global names to enable data to be connected across a multitude of
>      distributed, independently maintained data sources.  I could propose more
>      polished wording if desired.

Changed, see also earlier responses.

> --  "framework" -- or "language"?
>
>      I suspect the average reader will have no concept of "framework".  But if
>      RDF were called a "language" in the first paragraph, it could also be
>      called a language further down.  Specifically:
>
>          RDF allows us to make statements about resources
>
>      could be
>
>          RDF provides a language for making statements about resources

For the reasons stated above (not one language, but multiple) I prefer 
to keep it as is.

> --  "An RDF statement represents a relationship between two resources."
>
>      As the text goes on to say that the subject and object _represent_ the two
>      resources being related and the predicate _represents_ the nature of their
>      relationship, it seems more precise to say:
>
>          An RDF statement states a relationship between two resources.

I understand your point, but "statement states" is rather ugly. I 
suggest to replace "states" with "expresses", which is actually 
consistent with the first remark.

>
> --  "Resources typically occur in multiple triples"
>
>      This wording seems problematic because further down on that page, the text
>      lists IRIs, literals, and blank nodes as things that "occur in triples".
>      How about:
>
>          Resources, such as "Bob" and "The Mona Lisa", are typically the subject
>          or object of multiple triples.

This paragraph has been reworded based on suggestions of Bob DuCharme. I 
think this also takes care of your comment.

> --  "Informally speaking, RDF allows us to make statements of the form:"
>
>      What is informal here is not the fact that RDF allows us to make three-part
>      statements, but the informal syntax used to present them.  How about:
>
>          RDF allows us to make three-part statements such as the following
>          (expressed here, for readability, in pseudocode):
>
>      Maybe there is a better word for it than pseudocode, though I think it
>      sort of works.

Point taken. Remove "Informally speaking". The rest can be omitted, as 
there is a note immediately following the figure explaining the informal 
status of the syntax.

> --  Section 3.2 on IRIs in triples
>
>      The text _says_ that IRIs can appear in all three positions, but it only
>      provides example IRIs for a subject (The Mona Lisa) and an object
>      (Leonardo).  Perhaps the section could go one step further and introduce
>      the IRI for the property foaf:topic_interest (without waiting for Section
>      5.1).  Then it could show the triple:
>
>          <http://www.wikidata.org/entity/Q12418>
>              <http://xmlns.com/foaf/0.1/topic_interest>
>                  <http://dbpedia.org/resource/Leonardo_da_Vinci>

OK. I will include the "http://xmlns.com/foaf/0.1/knows" IRI.

It is too early here to show a full triple, as it requires explaining 
concrete syntax.

> --  Section 3.3 on Literals
>
>      The use of literals could then be illustrated with:
>
>          <http://www.wikidata.org/entity/Q12418>
>              <http://purl.org/dc/terms/title>
>                  "Mona Lisa"

Prefer not, again because it requires concrete syntax.

>
> --  Section 3.4 on Blank Nodes
>
>      I agree with Bob that this section is too brief and should either be
>      dropped (please not!) or expanded, perhaps with a diagram.
>
>      If RDF were called a language from the start, then blank nodes could
>      be explained by analogy to subordinate clauses.  For example:
>
>          Bob is interested in something which has the title "The Mona Lisa".
>
>      Trying to express this in the pseudocode of section 3 seems inadequate:
>
>          <Bob> <is interested in> <X>
>          <X> <has the title> <The Mona Lisa>
>
>      However, if the use of IRIs and literals in triples has just been
>      illustrated in the previous two sections, one could posit, for the sake of
>      argument that one does not know a URI for "Mona Lisa" and say:
>
>          <http://example.org/bob#me>
>              <http://xmlns.com/foaf/0.1/topic_interest>
>                  :blank_node_id1
>
>          :blank_node_id1
>              <http://purl.org/dc/terms/title>
>                  "Mona Lisa"
>
>      The accompanying diagram could be an adaptation of Figure 2.

See response to Bob DuCharme. We plan to include a figure. Again: prefer 
to not go into concrete syntax here.

>
> --  "For both classes and properties one can create subtype hierarchies".
>
>      Read in the context of the previous sentence ("The relation between an
>      instance and its class is modelled through the type property"), this could
>      be taken to mean that classes and properties can be sub-classed.  How
>      about:
>
>          One can create create hierarchies of classes and sub-classes or of
>          properties and sub-properties.
>
>      Also (s/modelled/stated):
>
>          The relation between an instance and its class is stated using the
>          type property.

Changed as suggested.

>
> --  "Type restrictions on the subjects and objects of particular triples can be
>      defined through domain respectively range restrictions"
>
>      This could be read as meaning that domain and range can be used to
>      "restrict" values in a closed-world sense.  Also, domains and ranges are
>      not defined for "particular triples" but for properties.  Maybe something
>      like (to be improved):
>
>          The types of resources associated with a given property in the context
>          of statements can be specified with a domain (for subjects) and range
>          (for objects).
>
>      It might be worth drawing this out a bit by emphasizing that domains and
>      ranges are about making inferencing possible, if it could be done briefly
>      and illustrated with a nice example.

This text was already changed in the way you suggest, based on other 
comments. Includes now also an example.

>
> ======================================================================
> The use of NOTEs
>
>      The NOTE blocks make good points but at the cost of interrupting the flow
>      of the text.  Calling out NOTEs as separate blocks has the effect of
>      drawing attention to the sort of detail I'd expect to find in footnotes.

We have reduced the number of Notes from 14 to 7. But we think the 
remaining ones are notes we would like to keep, in particular to point 
out background info.

>      Taking them note by note:
>
>      "This primer is..."
>
>          Maybe put in a separate, unnumbered section before the Introduction
>          called "About this document"?
>
>      "An IRI is..."
>
>          The notion that RDF uses IRIs as names for things is so fundamental
>          that it should be introduced in the first paragraph or two.  That
>          explanation could already state the relationship of IRIs to URIs and
>          URLs (as per section 3.2 and Bob's comments thereon).  Such an expanded
>          explanation would replace this NOTE.
>
>      "The RDF Data Model..."
>
>          That the RDF Data Model is expressed with an abstract syntax which is
>          independent of a particular [concrete syntax] is also a really key
>          point.  The notions "abstract syntax" and "concrete syntax" could
>          perhaps be defined in the Introduction by re-casting the list of
>          normative specifications as a list of things provided by the suite of
>          specs, e.g.:
>
>              The normative specifications of RDF define:
>
>              * The RDF Data Model, with an abstract syntax independent of any
>                particular concrete syntax ("RDF Concepts and Abstract Syntax")
>                [RDF11-CONCEPTS]
>
>              * Formal model-theoretic semantics ("RDF Semantics")[RDF11-MT]
>
>              * Several compatible concrete syntaxes -- different ways to
>                record RDF data in files for processing by applications:
>
>                ** Turtle...
>                ** JSON-LD...
>                ...
>
>              * A data-modeling vocabulary, RDF Schema [RDF11-SCHEMA].
>
>      "RDF is agnostic..."
>
>          Drop as a NOTE and fold into the explanation of IRIs in the Introduction.
>
>      "The RDF data model assigns the special datatype rdf:langString..."
>      "The 2004 version of RDF contained the notion of a 'plain literal'..."
>
>          Drop as NOTEs -- IMO these points are too detailed for the Primer.
>
>      "The IRI associated with the graph..."
>      "RDF provides no way to convey this semantic assumption..."
>      "Multiple graphs are a recent extension of the RDF data model..."
>
>          Drop as separate NOTEs and fold into the paragraph which starts with
>          "RDF 1.1 doesn't prescribe any specific semantics for datasets".
>
>      "The syntactic form... is in a prefix notation..."
>
>          Drop as a separate NOTE and fold into the explanation of IRIs in the
>          Introduction.
>
>      The remaining notes could similarly be folded into the text.  If the
>      content of the notes is too important to drop, perhaps the notes could all
>      be collected at the end as end notes.
>
> ======================================================================
> Copyediting suggestions
>
> --  "Web" and "web": Both are used. I suggest "Web", but either way, usage should be consistent.
>
> --  s/standard-compliant/standards-compliant/  (see http://en.wikipedia.org/wiki/Standards-compliant)
>
> --  "The format of these statements is simple.  It always has the following form:"
>
>      The use of "format" and "form" seems inconsistent, and the second sentence
>      could perhaps simply be dropped, leaving just:
>
>          The form of these statements is simple:
>
> --  "visualise": does W3C still officially prefer American spelling ("visualize")?
>
> --  "domain respectively range restrictions": This is an odd use of "respectively".  "Or"?
>

Changed as suggested.

Thanks again! Very helpful indeed. New ED is at [1].

Guus

[1] https://dvcs.w3.org/hg/rdf/raw-file/default/rdf-primer/index.html#
Received on Monday, 3 February 2014 15:35:51 UTC

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