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Re: Primer LCC, review.

From: Brian McBride <bwm@hplb.hpl.hp.com>
Date: Tue, 14 Jan 2003 19:18:43 +0000
Message-Id: <5.1.0.14.0.20030114191751.03272798@localhost>
To: Jan Grant <Jan.Grant@bristol.ac.uk>, RDFCore Working Group <w3c-rdfcore-wg@w3.org>

At 16:55 14/01/2003 +0000, Jan Grant wrote:

>A few trivial nitpicks. Appendix A actually anticipates the only issue I
>have with this document (although it basically says, "there is an issue,
>we don't deal with it").

Jan, am I right in reading this as a thumbs up for last call publication 
without change, i.e. no showstoppers.

Brian





>1. Introduction
>
>Figure 1 already includes the denotation/addressing issue I raised in
>the schema review. Is it purely accidental that Eric Miller's mailbox
>is named by a URI that also lets you address mail to him? I'd guess not.
>What are the conventions governing the use of such "suggestive"
>addressing names?
>
>In other words, why does this figure have the following triple:
>
><http://www.w3.org/People/EM/contact#me> 
><http://www.w3.org/2000/10/swap/pim/contact#mailbox> <mailto:em@w3.org> .
>
>and not this:
>
><http://www.w3.org/People/EM/contact#me> 
><http://www.w3.org/2000/10/swap/pim/contact#mailbox> _:a .
>_:a rdf:type eg:Mailbox .
>_:a rdfx:uri "mailto:em@w3.org"^^<xsd:uri> .
>
>or this (or some variant?)
>
><http://www.w3.org/People/EM/contact#me> 
><http://www.w3.org/2000/10/swap/pim/contact#mailbox> "mailto:em@w3.org" .
>
>[Come to think of it, why a mailto: and not an imap: url?]
>
>Following on from the example:
>
>"unlike conventional hypertext, RDF URIs can refer to any identifiable
>thing, including things that may not be directly retrievable on the Web"
>
>OK so far, but are there any distinguishing characteristics that can
>tell one kind of URI from another?
>
>(I note that this issue is addressed to some extent in Appendix A.)
>
>
>2.1 Basic Concepts
>
>The example is good, again, but has this: "In this statement, we've used
>the Web page's URL (Uniform Resource Locator) to identify it."
>
>OK, but how do I know that's what you've done? Is there some convention,
>or some magic associated with the domain of the creator property?
>
>In other words, there appears to be some restriction on valid
>interpretations of this statement that's got something to do with the
>URL labelling a resource being the address of a web page. I don't think
>this is articulated anywhere. I won't belabour this point though.
>
>Nitpick: "the object is the words..." should be "the object is the
>phrase" (currently doesn't agree on number)
>
>
>2.2 and onwards.
>
>I like this. The document in general is an easy read, the pictures are
>colourful and straight-forward, and there are lots of examples. The
>narrative structure is good and the whole thing smacks of eloquence and
>polish. A very nice job.
>
>
>Namespace prefix definitions: there's an example which includes -
>
>         ex:index.html dc:creator exstaff:85740 .
>
>Again, this tacitly ignores the fact that ex:index.html appears to name
>a web page, and exstaff:85740 appears to name a person; but they both
>look like URLs to me. I don't hold the primer at fault here, because
>this goes on a lot in RDF in the wild (it seems) - I'd be satisfied with
>some way of telling which was which.
>
>
>2.3, Figure 6 explanatory text:
>
>This is not a bad stab at explaining the graph-specific identity of
>blank nodes in a "see spot run" stylee :-) In addition, there follows
>some excellent text about not using things that look like URLs to name
>things that don't have URLs (eg, people). This is a really important
>idea (blank nodes everywhere?) and it's introduced well. Hopefully it
>won't get lost in passing.
>
>In fact, it's worthwhile considering if this idea (obvious as it may
>seem) isn't worth extracting into a separate note, because it's really,
>really important, and Eric and Frank have done a good job of explaining
>it.
>
>
>2.5. Concepts summary
>
>Nitpick (numbering format change in heading)
>
>
>4.1 RDF Containers
>
>Example 14 and Figure 15 contains example1.org and example2.org domains:
>are these reserved for example use? How about ftp1.example.org, etc?
>
>
>4.4 rdf:value
>
>I'm really uncertain whether rdf:value deserves the excellent treatment
>here. It seems to me that other modelling approaches are more likely to
>be successful in the long run (eg, factoring units into the property
>definitions, so "exterms:weight" is defined as "weight in kilogrammes"),
>although I'm ready to be set straight on that point (I've a sneaking
>suspicion that there may be reasonable counterexamples in the iCalendar
>world). I'd like at least to see an alternative mentioned (although
>perhaps the primer isn't the place for this).
>
>
>5.3 Interpreting RDF Schema Declarations
>
>Another eloquent exposition of an important thesis. Last paragraph is
>one of those that'd definitely have to be in one of those mythical
>cut-down "views" of the primer text :-)
>
>
>6.1 Dublin Core
>
>The dc:subject is an rdf:Bag in the example. I'm _still_ not sure what
>this means, particularly given the description of rdf containers
>previously in the document (the prose related to the example in 4.1
>concerning a rules committee would seem to imply that the rdf:Bag should
>not have been used). I seem to recall discussing this around in circles
>before now; I don't recall the conclusion.
>
>
>6.2 PRISM
>
>"For example, dc:date is extended by properties like
>prism:publicationTime, ..." Technically, isn't it restricted or
>constrained, not extended? Maybe "speciali[sz]ed"?
>
>
>Appendix A.
>
>"People sometimes use RDF together with a convention that, when a URIref
>is used to identify an RDF resource, a page containing descriptive
>information about that resource will be placed on the web "at" that
>URI...However, this convention is not an explicit part of the definition
>of RDF, and RDF itself does not assume that a URIref identifies
>something that can be retrieved."
>
>Fair enough, and perhaps this is all the RDF specs need to say on the
>subject, but since there's a "Web" in "the Semantic Web" I'd hope that
>someone, somewhere, is going to say more about this (TAG?).
>
>
>
>Summary:
>
>I really like this. It's quite a dense document and I'll be reading it
>again to see if there's anything I've missed (third time lucky?);
>thumbs-up to publish.
>
>
>
>--
>jan grant, ILRT, University of Bristol. http://www.ilrt.bris.ac.uk/
>Tel +44(0)117 9287088 Fax +44 (0)117 9287112 http://ioctl.org/jan/
>Goth isn't dead, it's just lying very still and sucking its cheeks in.
Received on Tuesday, 14 January 2003 14:17:26 EST

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