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Re: Review of RDF primer Revised Editor's Draft 21 July 2003

From: Frank Manola <fmanola@mitre.org>
Date: Wed, 30 Jul 2003 15:42:50 -0400
Message-ID: <3F281FBA.B0E6B561@mitre.org>
To: Dave Beckett <dave.beckett@bristol.ac.uk>
CC: w3c-rdfcore-wg@w3.org, Eric Miller <em@w3.org>

Just replying to the problematic bits (and asking for comments from the
WG, not just replying to Dave):

Dave Beckett wrote:
> Review of
> http://www.w3.org/2001/sw/RDFCore/TR/WD-rdf-primer-20030117/Overview.html
> Last Modified: 07/25/03 15:34:11
> 400691 bytes
> Paragraph "Since the value..."
> Not sure I like the [["first among equals" status in RDF.]] quote.
> Who said that?  Has it any cultural problems?

Brian said it (he did it! he did it!).  It was in the LC version and no
one complained.  If it's inappropriate to say it this way, we need to
find some other words to explain why we talk explicitly about the XML
Schema datatypes (in Primer, Concepts, Semantics, ...) and no others. 
But I think "first among equals" captures it pretty well.

> Last Paragraph of 2.4
> Do "proper" and "intended interpretation" have some special meaning?
> There is a definition in RDF Semantics about this which might be
> useful, where "bad" datatypes are not RDF literals, under a
> particular datatype entailment such as XSD-datatype-entailment.
> I'm not sure how to easily translate that into simpler terms!
> Maybe intended interpretation does work.  Your choice.

My choice is to leave it alone!

> Paragraph "Example 7 illustrates"... "For readability"
> On entities - in this case only entities defined in the document,
> i.e. in the "internal DTD subset" are likely to work.
> You can use RDF/XML with a DTD and probably could do things
> like declare entities there (or default attributes on elements etc. -
> trickier since there is no DTD for RDF/XML) but we really
> should encourage that.
> Anyway, that's just information or advice.  Which might belong here.

I'm basically following the model of the OWL specs here (DOCTYPE and

> Paragraph "As noted"
> you mention well-formed here, but the caption on example 16 uses
> "ill-formed".

"ill-formed" was intended to be equivalent to "not-well-formed".  Do you
think the latter is better?

> 4.2 RDF Collections
> [paragraphs after example 16]
> Seems ok updated for the implicit rdf:type rdf:List although
> it may not be clear that this is RDFS entailment and not RDF.

Yeah, but I don't see how this distinction can be made very well here.

> 4.5 XML Literals
> [I assume this section is still in a bit of flux]


> 5.1 Describing Classes
> Paragraph "The meaning of this rdfs:subClassOf ..."
> I see the use of an "RDF processor" and "RDF schema software"
> The latter you define, but not the former.  If you could avoid
> both that would be good.

If you could suggest some alternatives, that would be even better.  DanC
wants to talk only about "languages", which is fine in principle, and I
appreciate that we are not "defining a processing model" (as this is
generally put).  The problem is that we don't really have distinct
languages in the sense lots of people think of languages being
distinct.  Given an RDF schema, this is *both* RDF and RDFS.  The
difference between the "languages" is whether particular conclusions can
be drawn from particular pieces of reserved vocabulary or not.  Pat
describes this in terms of different kinds of entailments, but that
doesn't seem appropriate in the Primer, and saying "conclusions can be
drawn", being passive voice, elides the issue of who or what does the
conclusion-drawing.  I think characterizing this difference in the
Primer as one between different kinds of software (or software written
to understand different stuff) is reasonably clear, and it's not clear
to me what the problem is in saying that way in a non-normative document
(e.g., what inappropriate entailments are introduced?).  But I'll be
happy to entertain alternative ways of saying the same thing.

> Example 22 should have an xml:base, since it has rdf:IDs
> [example 23 does].  Later after example23 you mention use
> of xml:base so I expect you should change the rdf:IDs in
> example 22 to be full URIs.

Why?  rdf:IDs work relative to the document don't they?  

> Example 24 - !
> Yes, it's correct but I'm sure people will get burnt with this kind
> of thing.

What kind of thing?  If you mean not using an xml:base, the text says
they ought to use one.

> Maybe you could explain the benefit (is there only one? :) of rdf:ID
> - checking for duplicates in 1 document so that people can see when
> it makes sense to use it.

How important is this;  like, how many sentences is it worth?  :-)

> 6.3 XPackage
> Example 37 includes this inside the rdf:
>       <xpackage:location xlink:href="doc.html"/>
> That is not RDF/XML, unless they meant this to be
>       <xpackage:location>
>         <rdf:Description>
>            <xlink:href>doc.html</xlink:href>
>         </rdf:Description>
>       </xpackage:location>
> In particular doc.html is not a URIref.
> Ditto for example 38.
> If however, these are not RDF/XML, this does not apply.

I'll have to look at the xpackage spec itself to check this out.

> 6.6 Gene Ontology Consortium
> This syntax is bizarre, what is it doing in an RDF primer?

To illustrate a use of RDF in the field.  

> Please label Example 42 clearly with "not RDF/XML" in the caption
> or give it style that shows it's not something people should try as
> real RDF/XML.

The text says so, but OK.

> Appendix A: More on Uniform Resource Identifiers (URIs)
> Please label the state of this and other appendices in or near the
> titld - this one is informative, but for the definitive use of URIs,
> see RFC2396.

I'm not sure I understand.  The whole Primer is informative, so
obviously the Appendices are.  I can emphasize that the defining spec is
RFC2396 in the text.

> Appendix B: More on the Extensible Markup Language (XML)
> Ditto, "see XML 1.0 (Second edition)" for definitive info.

If this is also what you meant for URIs, that's fine.

> Paragraph "Finally, XML provides ...
> Well, it is finally here, but XML provides lots of stuff and if you
> include all the XML things that we do (XML, Namespaces, Infoset,
> Base, Canonicalization, [schema]) then it's just a small intro, which
> is the case.

Could you translate this? :-)

> spelling "Entitites"
> I'd again avoid recommending or mentioning use of external DTDs.
> Since RDF/XML uses the infoset that does not require validation,
> use of external DTDs is possible but unlikely.
> Example 46 is an internal DTD subset

I don't think I explicitly mention external DTDs, but maybe it's
implicit from the syntax.  I'll see if I can tighten this up.  

> You might take the blank lines out before and after <!DOCTYPE> - some
> parsers are sensitive to that.

Do you think it's equally readable having done that (I'm more worried
about human readers than XML parsers!)?


Frank Manola                   The MITRE Corporation
202 Burlington Road, MS A345   Bedford, MA 01730-1420
mailto:fmanola@mitre.org       voice: 781-271-8147   FAX: 781-271-875
Received on Wednesday, 30 July 2003 15:44:03 UTC

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