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Re: Proposal to resolve ISSUE-102 (well-formed lists)

From: Dan Brickley <danbri@danbri.org>
Date: Fri, 9 Nov 2012 11:57:24 +0000
Message-ID: <CAFfrAFrpUPhL4bp3eoeL0cvvrSTzj8r8D5qVdhRWM2V8Hq-Zog@mail.gmail.com>
To: Richard Cyganiak <richard@cyganiak.de>
Cc: RDF Working Group WG <public-rdf-wg@w3.org>
On 9 November 2012 11:26, Richard Cyganiak <richard@cyganiak.de> wrote:
> Dan,
> You're a master of vagueness.

Why, thank you. Flatterer.

> Are these your concerns?
> 1. You believe that RDFS should avoid any kind of conformance statements, including RECOMMEND-level statements on the use RDFS terms.

I don't believe I said or suggested that. Rather, that the kind of
conformance we've historically dealt with has been about the *meaning*
of RDF/RDFS terms. If you don't use them in accord with their meaning,
you can expect to pay the price of confusion and miscommunication; so
if you don't want confusion and miscommunication you should stick to
their official meaning. More in the concrete syntaxes / grammars have
we talked about whether documents conform. I'm over generalising;
'conform' appears in http://www.w3.org/TR/rdf-mt/ in a few ways,
ranging from structure of literals, to 'conformance to semantics'. The
sense you're suggesting here seems more that we're introducing a
notion of 'good' vs 'bad' graphs. Can that be made more explicit?

> 2. You are concerned that the proposal is not phrased as actual literal spec text. Thus is does not yet spell out all the details that would enable you, as the editor of the spec, to assess whether the text is appropriate for the spec.

Well, since you're praising my vagueness, I'll praise yours. Details
would help. But I think there's enough here to work with, since the
general direction is clear. But yes, I would like to know whether you
think the full rules can be written out, and how they interact with
the various entailment regimes that might be in play.

(excuse the notation)

#foo subPropertyOf rdf:next .
#x foo #y .
#a a owl:InverseFunctionalProperty .
#x #a #bar .
#y #a #bar .

would such a graph violate the SHOULD, for concrete example?

The intent here, if I got example right, is that x and y are indicated
by common inverse functional property to be names for the self-same
entity, introducing a loop into the 'next' link, which itself is
mildly complicated by subproperty. Doubtless logicians can cook up
more fiendish examples.

> 3. You believe that “graph containing no malformed lists” is a more useful concept than “graph consisting only of one well-formed list”.

Either would be fine. It was an illustrative example, suggesting a way
of couching SHOULD-speak in more RDF-flavoured declarative terms.
Whenever we see SHOULD, we can ask, 'who should do what, when?'. That
kind of language generally works well if talking about classes of
software component, service or document. My sense here is that we're
talking about classes of document/graph, and I'd prefer to clarify
that and make it explicit before leaping in to the specifics.


Received on Friday, 9 November 2012 11:57:51 UTC

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