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Re: proposed second reply to Jeremy's comment about named graphs

From: Peter Patel-Schneider <pfpschneider@gmail.com>
Date: Wed, 11 Sep 2013 20:19:27 -0700
Message-ID: <CAMpDgVwJ-8fZL4LvTUVbMcSO2hDtdiMwBFd55yNFDh_Ni3S6qg@mail.gmail.com>
To: Sandro Hawke <sandro@w3.org>
Cc: RDF WG <public-rdf-wg@w3.org>
I read over all the emails in this long discussion carried out on
public-rdf-comments, including all the emails that you reference.   I did
not want to get bogged down in the weeds, and thus only brought forward the
impossibility of doing *anything* more than what was already done.

We could, I suppose, put the proposals that Jeremy has put forward up to a
vote in the WG next week.  My vote is "NO!".

Note that Jeremy cannot be proposing that the names of RDF graphs denote
the graphs.  Otherwise he would have said "yes" at the beginning of
http://lists.w3.org/Archives/Public/public-rdf-comments/2013Sep/0010.html

Jeremy's test case in that message also pulls in owl:imports and other OWL
vocabulary.   The RDF Working Group has nothing to say about owl:imports or
other structural OWL vocabulary.  Any examples that use this vocabulary
must be viewed with extreme suspicion.


peter



On Wed, Sep 11, 2013 at 7:41 PM, Sandro Hawke <sandro@w3.org> wrote:

> On 09/11/2013 08:43 PM, Pat Hayes wrote:
>
>> I like this. Is it a good idea to also refer to the notes that Sandro and
>> Pierre-Antoine are supposed to be writing? Just to show we havnt stopped
>> worrying about it, you understand.
>>
>
> There's seems to be some lack of community memory on this.  I already gave
> Jeremy the formal reply to Jeremy's rdf:Graph comment, in which I explained
> about those two notes, etc [1].   He said he still wasn't happy [2].    I
> asked for more details [3], and he gave test cases [4] and proposed text
> [5].   I think we need to respond to *those* not to his earlier comments.
>
> [1] http://lists.w3.org/Archives/**Public/public-rdf-comments/**
> 2013Aug/0050.html<http://lists.w3.org/Archives/Public/public-rdf-comments/2013Aug/0050.html>
> [2] http://lists.w3.org/Archives/**Public/public-rdf-comments/**
> 2013Sep/0005.html<http://lists.w3.org/Archives/Public/public-rdf-comments/2013Sep/0005.html>
> [3] http://lists.w3.org/Archives/**Public/public-rdf-comments/**
> 2013Sep/0007.html<http://lists.w3.org/Archives/Public/public-rdf-comments/2013Sep/0007.html>
> [4] http://lists.w3.org/Archives/**Public/public-rdf-comments/**
> 2013Sep/0010.html<http://lists.w3.org/Archives/Public/public-rdf-comments/2013Sep/0010.html>
> [5] http://lists.w3.org/Archives/**Public/public-rdf-comments/**
> 2013Sep/0017.html<http://lists.w3.org/Archives/Public/public-rdf-comments/2013Sep/0017.html>
>
> I haven't yet had a chance to read and think about [4] and [5].
>
>        -- Sandro
>
>
>
>
>  Pat
>>
>> On Sep 11, 2013, at 1:28 PM, Peter Patel-Schneider wrote:
>>
>>  Dear Jeremy:
>>>
>>> This is a second official response to your comment about named graphs in
>>> http://lists.w3.org/Archives/**Public/public-rdf-comments/**
>>> 2013Jul/0021.html<http://lists.w3.org/Archives/Public/public-rdf-comments/2013Jul/0021.html>and
>>> http://lists.w3.org/Archives/**Public/public-rdf-comments/**
>>> 2013Sep/0005.html<http://lists.w3.org/Archives/Public/public-rdf-comments/2013Sep/0005.html>
>>>
>>>
>>> The RDF Working Group believes that there are several ways in which RDF
>>> graphs and datasets are and will be used.  These include ways that fit
>>> into
>>> your use cases, where the graph names denote the graph they name or some
>>> other formal graph-related construct and where you would indeed say
>>> something like
>>>
>>> jjc:graph {
>>>    jjc:graph dc:creator "Jeremy J. Carroll" .
>>> }
>>>
>>> However, there are also ways that do not fit into your use cases, for
>>> example where the graph names are IRIs that denote some other entity,
>>> such
>>> as
>>>
>>> jjc:jjc {
>>>    jjc:jjc rdf:type foaf:Person .
>>>    jjc:jjc foaf:lastName "Carroll" .
>>>    jjc:jjc foaf:knows jjc:pfps .
>>> }
>>>
>>> If the RDF semantics required that all graph names denote graph-related
>>> constructs this would interfere with these other use cases.  Therefore
>>> the RDF
>>> Working Group decided to not so require.
>>>
>>> Further the RDF Working Group was unable to agree on even a weak theory
>>> of
>>> named RDF graphs, such as one conditioned on explicit typing.  Even the
>>> nature of what graph names might denote was problematic: does the name
>>> of an
>>> RDF graph denote the graph itself, does it denote some other construct
>>> that
>>> is related to the graph, or does it even denote the semantic meaning of
>>> the
>>> graph?
>>>
>>> Therefore the working group has produced a very minimal specification for
>>> RDF datasets and named graphs that does not depend on denotation.
>>>
>>> This approach produces maximally compatability, but does not produce
>>> inferences that might be desirable in some use cases.  If you do want
>>> certain inferences to be part of your approach, such as the first example
>>> above entailing
>>>    jjc:graph rdf:type jjc:Graph.
>>> you can define and implement a particular RDF entailment regime that
>>> sanctions these inferences.
>>>
>>> The RDF Working Group believes that this minimal approach will allow
>>> different approaches to named graphs to coexist some allowing what you
>>> want
>>> and others incompatible with what you want.  The flourishing approaches
>>> can
>>> then be considered for standardization at a later time.
>>>
>>>
>>>  ------------------------------**------------------------------
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>>
>>
>>
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>
Received on Thursday, 12 September 2013 03:19:55 UTC

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