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Re: Proposed change to the charter, section 4. Deliverables, Recommendation Track

From: Peter F. Patel-Schneider <pfpschneider@gmail.com>
Date: Wed, 06 Aug 2014 15:44:13 -0700
Message-ID: <53E2AFBD.9050102@gmail.com>
To: Holger Knublauch <holger@topquadrant.com>, public-rdf-shapes@w3.org
Well, I did present what I thought was a good neutral set of deliverables, namely

1. A syntax and semantics for shapes specifying how to construct shape
expressions and how shape expressions are evaluated against RDF graphs.

2. An RDF vocabulary for expressing these shapes in RDF triples, so they can
be stored, queried, analyzed, and manipulated with normal RDF tools.

3. OPTIONAL A specification of how shape verification interacts with
inference.

4. OPTIONAL A compact, human-readable syntax for expressing shapes.

peter



On 08/03/2014 03:57 PM, Holger Knublauch wrote:
> Hi Peter,
>
> this mailing list provides plenty of evidence that OWL is not expressive
> enough and something on the level of SPARQL is needed. ShEx has an escape
> mechanism to fall back to SPARQL [1], and IBM has explicitly stated that this
> is required too [2]. OWL cannot even do basic math or string operations,
> neither does it have a concept of "variables" that is very much needed to do
> complex joins. So as a minimum, the outcome of this group should be to agree
> on a high-level vocabulary (possibly OWL and/or Shapes) plus a mechanism to
> represent other cases with something like SPARQL. Do you agree so far?
>
> Yes, OWL does have a very large overlap with the Shapes that were originally
> submitted (mainly cardinalities and ranges). So it is a valid question whether
> both are needed. But if you look at the SPIN specification you may notice that
> once you have a mechanism such as SPIN (with templates) in place, it becomes
> quite trivial to add any number of libraries including the "Shapes"
> implementation that I presented a while ago [3]. And this library can cover
> many more use cases than either the current Shapes proposals nor OWL closed
> world can represent, see for example [4] and [5]. Could you clarify whether
> your goal is to prevent "Shapes" becoming a standard and use OWL instead?
>
> I believe it is easy to just say no to everything. Have you worked out a
> better proposal? How should the charter look like from your point of view?
>
> Thanks
> Holger
>
>
> [1] http://www.w3.org/Submission/shex-primer/#semact
> [2] http://lists.w3.org/Archives/Public/public-rdf-shapes/2014Jul/0246.html
> [3] http://lists.w3.org/Archives/Public/public-rdf-shapes/2014Jul/0237.html
> [4] http://semwebquality.org/mediawiki/index.php?title=SemWebQuality.org
> [5] http://lists.w3.org/Archives/Public/public-rdf-shapes/2014Aug/0040.html
>
>
> On 8/4/2014 3:33, Peter F. Patel-Schneider wrote:
>> I do not support this approach at this time.  To me it looks too much like
>> having two standards for the same thing.  I feel that the SPARQL-based
>> approach and the model-checking approach (which is what OWL+CWA boils down
>> to for RDF graphs) have quite a large overlap in their capabilities, even
>> though they may look quite different technically.
>>
>> It may be that I am wrong in this, of course, and that there are good
>> reasons to split in this way.
>>
>>
>> peter
>>
>>
>> On 08/02/2014 11:21 PM, Holger Knublauch wrote:
>>> A pragmatic proposal: I do believe there is consensus that this WG can
>>> potentially create some useful and relevant output that could lead to broader
>>> use cases for semantic web technology as a whole. There are several proposals
>>> on the table that are potentially complementary to each other. Assuming there
>>> are enough people who actually sign up for the work, why not produce multiple
>>> deliverables that cover more use cases?
>>>
>>> 1) Shapes + SPIN, with an explicit mandate to have semantics that are
>>> executable by SPARQL engines, from day one. The alternative would be ShEx and
>>> this could be figured out in the beginning of the WG. This deliverable would
>>> be like an extension to SPARQL.
>>>
>>> plus
>>>
>>> 2) OWL closed world semantics, so that existing OWL ontologies can be reused.
>>> This deliverable would basically be an "appendix" to the OWL 2 spec.
>>>
>>> This would allow the interest groups to stay on their home turf without
>>> blocking each other, because blocking each other would be the worst outcome of
>>> all. I see no technical difficulties with such as stack, because these
>>> technologies are complementary to each other: we use OWL closed world + SPIN
>>> all the time, and it works well in practice. In fact I believe both
>>> specifications have a good and stable starting point so that we could proceed
>>> with the process very swiftly.
>>>
>>> Peter, would this be an acceptable direction for you?
>>>
>>> Thanks,
>>> Holger
>>>
>
>
Received on Wednesday, 6 August 2014 22:44:42 UTC

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