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

I don't see much wrong in pointing at potential solutions, and even less 
mentioning possible starting points, but that's not what the proposed change 
to the charter is.  Instead the proposed change mandates SPARQL as the 
semantics of constraints.  I think that this is in advance of any worked-out 
proposal for actually using SPARQL for this purpose.

If it turns out that SPARQL can be used to specify the semantics of 
constraints, then it may be reasonable to use SPARQL for this purpose. 
However, mandating SPARQL's use even before its suitability has been 
demonstrated doesn't seem to me to be a good idea.

peter


On 08/01/2014 06:54 PM, Irene Polikoff wrote:
> Not necessarily. As Jeremy Carroll said in one of the previous e-mails "W3C experience indicates that a WG with a blank sheet at the beginning often delivers the wrong stuff, late - and the broad ship that sails ends up as a narrow clique on arrival".
>
> It is better to set a charter that identifies the prime candidate. As the work proceeds, the group may decide that the candidate doesn’t meet key requirements, but having initial stake in the ground is important to the effectiveness of the group, its ability to deliver on time and quality of its deliverables.
>
> Irene
>
> -----Original Message-----
> From: Peter F. Patel-Schneider [mailto:pfpschneider@gmail.com]
> Sent: Friday, August 01, 2014 5:53 PM
> To: Arthur Ryman; public-rdf-shapes@w3.org
> Subject: Re: Proposed change to the charter, section 4. Deliverables, Recommendation Track
>
> All these arguments may be fine, but isn't that up to the working group to decide?
>
> peter
>
>
> On 08/01/2014 02:42 PM, Arthur Ryman wrote:
>> Peter,
>>
>> Thx for the response. I'm glad that we agree on making the compact,
>> human-friendly syntax optional.
>>
>> Here is my rationale for advocating for the use of SPARQL.
>>
>> 1. We need to be precise about the meaning of constraints. Therefore,
>> we need to select some formalism for expressing the semantics.
>>
>> 2. The candidates for expressing semantics include:
>> 2.1 Natural language
>> 2.2 OWL ICV
>> 2.3 SPARQL
>> 2.4 Z
>> 2.5 some other existing formal language
>> 2.6 a new specification language that the wg invents
>>
>> Pros and Cons
>>
>> 2.1 Natural language is imprecise and non-executable
>> 2.2 OWL ICV is well-defined and executable, but not a W3C standard and
>> is not expressive enough as a general constraint language
>> 2.3 SPARQL is a W3C standard, is very expressive, and is executable
>> 2.4 Z is very expressive but not well known and is non-executable
>> 2.5 There are many other formal specification languages. Does anyone
>> want to advocate for one?
>> 2.6 A new formalism - not the core focus of the workgroup.
>>
>> 3. Some one will need to build a reference implementation. A SPARQL
>> implementation will be easy to build if the semantics of the
>> constraints are in SPARQL.
>>
>> 4. We want the specification to be implemented and adopted. SPARQL is
>> a known quantity and many implementations exist.
>>
>>
>> Regards,
>> ______________________________________________________________________
>> _____
>> Arthur Ryman, PhD
>>
>> Chief Data Officer, Rational
>> Chief Architect, Portfolio & Strategy Management Distinguished
>> Engineer | Master Inventor | Academy of Technology
>>
>> Toronto Lab | +1-905-413-3077 (office) | +1-416-939-5063 (mobile)
>>
>>
>>
>>
>>
>> From:   "Peter F. Patel-Schneider" <pfpschneider@gmail.com>
>> To:     Arthur Ryman/Toronto/IBM@IBMCA, public-rdf-shapes@w3.org,
>> Date:   08/01/2014 05:22 PM
>> Subject:        Re: Proposed change to the charter, section 4.
>> Deliverables, Recommendation   Track
>>
>>
>>
>> I do agree that the emphasis in the charter on creating a
>> human-readable syntax is misplaced and that this deliverable should be
>> made optional. The proposal here, however, does very much more than
>> fixing this problem, and I view most of the other changes in the
>> proposal as undesirable.
>>
>> Why should the group be required to specify semantics in terms of SPARQL?
>> There hasn't even been anything to show that SPARQL is adequate for
>> this purpose.  Why should the group be required to specify two ways of
>> expressing constraints, and one of them be SPARQL itself?  There
>> hasn't been anything to show that this division is needed.  Why should
>> a human-readable syntax for constraints be new?  There hasn't been
>> anything to show that existing syntaxes are unsuitable for this
>> purpose.  I don't think that it is appropriate to tie the hands of the
>> working group in any of these ways.
>>
>> I do agree that the group should be required to define the meaning of
>> constraints.  This was a peculiar lack in the deliverables.
>>
>> So my proposal would be to change the recommendation track
>> deliverables to
>>
>> something like:
>>
>> 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.
>>
>> I would prefer the third deliverable to be required, but I'm not going
>> to complain if it is optional.
>>
>> Although there are three syntaxes mentioned in these deliverables, in
>> keeping with the usual RDF situation there is nothing saying that all
>> of these three need to be different or even that they are not all the
>> same.  (Well, nothing beyond the implausibility of using RDF triples
>> as the basis of a compact, human-readable syntax.)
>>
>> peter
>>
>>
>> On 08/01/2014 12:44 PM, Arthur Ryman wrote:
>>> The output of the wg is defined by its deliverables. Here is the
>>> current text [1]
>>>
>>> Recommendation Track:
>>> 1.      Compact, human readable syntax for expressing constraints on RDF
>>> graph patterns (aka shapes), suitable for the use cases determined by
>> the
>>> group. This syntax might be a variation of an existing standard, such
>>> as templates for SPARQL, or something new, such as ShExC.
>>> 2.      An RDF vocabulary, such as Resource Shapes 2.0, for expressing
>>> these shapes in RDF triples, so they can be stored, queried,
>>> analyzed,
>> and
>>> manipulated with normal RDF tools.
>>> The WG MAY produce a Recommendation for graph normalization.
>>>
>>> This text is not acceptable to IBM because of the primary emphasis it
>>> places on defining a possibly new compact, human readable syntax. I
>>> believe this concern has been expressed repeatedly by many people on
>>> the mailing list. Many people have indicated a strong preference for
>> building
>>> on existing standards. However, we have not seen any corresponding
>>> modification of the charter. I'd therefore like to propose a strawman
>>> change to this section of the charter and invite comment. Here is the
>>> proposed new text:
>>> The WG MUST produce:
>>> 1. A high-level RDF vocabulary that expresses commonly occurring
>>> constraints.
>>> 2. The semantics of the high-level constraints expressed in terms of
>>> SPARQL.
>>> 3. An RDF extension mechanism for expressing additional constraints,
>>> expressed in SPARQL.
>>> The WG MAY produce:
>>> 1. A new compact, human readable syntax for expressing constraints
>>> with
>> a
>>> corresponding semantics expressed in SPARQL.
>>> 2. A specification for graph normalization.
>>> [1] http://www.w3.org/2014/data-shapes/charter
>>>
>>> Regards,
>>>
>> ______________________________________________________________________
>> _____
>>> Arthur Ryman, PhD
>>>
>>> Chief Data Officer, Rational
>>> Chief Architect, Portfolio & Strategy Management Distinguished
>>> Engineer | Master Inventor | Academy of Technology
>>>
>>> Toronto Lab | +1-905-413-3077 (office) | +1-416-939-5063 (mobile)
>>>
>>>
>>>
>>
>>
>>
>>
>
>

Received on Saturday, 2 August 2014 05:17:38 UTC