Re: Two Standards ?

I think it may be useful for the F2F meeting to have on the agenda a
question on what to use to describe semantics of constraints.

LDOM uses SPARQL as a way to formally describe semantics. Thus, there isn't
really a "translation" between LDOM and the underlying semantics. There
could be other proposals for the formalisms to use. The pros and cons need
to be discussed.

On Fri, Feb 13, 2015 at 5:06 PM, Solbrig, Harold R. <Solbrig.Harold@mayo.edu
> wrote:

>  Folks,
>
>  Apologies for not catching the call for feedback below.  I very much
> like Hoger's suggestion, "Another option would be to define a compiler from
> ShExC into LDOM RDF and back", as it would get us closer to our
> (Mayo/CIMI's)  primary goal — a formal definition of the *semantics* of
> RDF data shapes.  If we can compile back and forth, we are (hopefully)
> demonstrating semantic equivalence.  The Mayo/CIMI goal is to arrive at:
>
>    1. A consistent set of semantics for the specification of Shape
>    Expressions
>    2. At least one grammar/syntax that can formally represent these
>    semantics
>
> We (again – Mayo/CIMI)  would hope that the grammar meets some of our own
> goals in terms of succinctness, understandability and the like but we will
> be able live with whatever comes out as long as it fulfills our semantic /
> functional requirements.
>
>  It is quite likely that we will end up using other representational
> forms in some of our projects in any case (one of the representations that
> we have waiting in the wings is UML). While it might be helpful to have
> community buy in on those other forms, it isn't essential as long as we can
> demonstrate that there is an isomorphism between our representation and the
> (or "a")  standard representational form.   I see uses for both ShExC and
> LDOM RDF and, as long as we can agree that they are (or share) different
> representations for the same thing, then we will be quite happy.
>
>  Arguing about whether ShExC, LDOM RDF or some other representation is
> the right way to go is, in my mind, kind of like arguing on the syntax of
> Turtle vs RDF/XML without first agreeing on the underlying model of RDF
> itself.  The representations are essential, in the sense that it is danged
> hard to talk about a model without having a succinct grammar to do so, but
> we need to use a first approximation of some grammar to discuss the model
> and, only then, to create final specification(s) for various
> representational forms.
>
>  I would propose that we declare at the outset that we want both ShExC
> and LDOM RDF to be able to represent the same core semantics (I say "core"
> because I wouldn't object to either or both of them having additional but
> optional features that go beyond the core specification).  Lets use
> whatever formalism makes the most sense in a given context to explain what
> a given constraint should do and, once we've arrived at some sort of
> consensus, record the decision using formal logic.  A final step would be
> to adjust the designs of one or both languages so that we know exactly what
> an expression means and how the two align.
>
>  Harold Solbrig
> Mayo Clinic
>
>
>   From: Holger Knublauch <holger@topquadrant.com>
> Date: Friday, February 13, 2015 at 3:30 PM
> To: RDF Data Shapes Working Group <public-data-shapes-wg@w3.org>
> Subject: Re: Two Standards ?
> Resent-From: <public-data-shapes-wg@w3.org>
> Resent-Date: Friday, February 13, 2015 at 3:30 PM
>
>  The upcoming F2F meeting is supposed to deliver the general direction,
> select editors and deliverables [1]. I don't think my proposal here is
> premature at all. In fact it touches on the very fundamental questions that
> Peter suggested we discuss too.
>
> Holger
>
> [1] https://www.w3.org/2014/data-shapes/wiki/F2F2#Objectives
>
>
> On 2/14/15 7:03 AM, Michel Dumontier wrote:
>
> I think all this discussion premature and counter to the intended focus of
> this WG. Stay focused on delivering the promised outcomes.
>
> m.
>
>  Michel Dumontier, PhD
> Associate Professor of Medicine (Biomedical Informatics)
> Stanford University
> http://dumontierlab.com
>
> On Fri, Feb 13, 2015 at 12:06 PM, Holger Knublauch <holger@topquadrant.com
> > wrote:
>
>> My concern is not about personal preferences, but about language(s) that
>> end users will actually want to use. We already struggle to understand
>> shapes versus classes within the WG. The separation that I propose would
>> allow us to write two different primers that will be consistent to
>> understand and use.
>>
>> If the charter does not give us the possibility to define two standards,
>> then this becomes a matter of packaging. One approach is to introduce a
>> small Abstract Syntax for the commonality between LDOM and ShExC. This may
>> include something like the Shape Selectors, but not in RDF but "abstract".
>> Another option would be to define a compiler from ShExC into LDOM RDF and
>> back (I had proposed that before [1] without getting feedback). Both
>> concrete syntaxes could still have a similar name, if that helps with the
>> standardization process.
>>
>> I also assume that WGs are still allowed to slightly diverge from the
>> original Charter if they justify their reasons for doing so - at least that
>> is what I was told when we wrote the original charter. I believe the
>> discussions over the last half year (and potentially another half a year
>> well into 2015) provide some of those reasons. Also, producing a Compact
>> Syntax has been mentioned in the charter.
>>
>> Holger
>>
>> [1]
>> https://lists.w3.org/Archives/Public/public-data-shapes-wg/2015Jan/0223.html
>>
>>
>>
>>
>> On 2/14/15 5:07 AM, Arnaud Le Hors wrote:
>>
>> I don't think there is evidence yet that a common solution can't be
>> found. Yesterday's strawpoll tells me there is hope we can find some common
>> ground to build on to produce a standard that we can all live with. This
>> may not be anyone's personal preference but standards are typically not.
>>
>> It may be that eventually some will seek to define other standards but
>> this won't happen here. Our charter doesn't give us that possibility.
>> --
>> Arnaud  Le Hors - Senior Technical Staff Member, Open Web Technologies -
>> IBM Software Group
>>
>>
>>
>>
>> From:        Dean Allemang <dallemang@workingontologist.com>
>> <dallemang@workingontologist.com>
>> To:        Holger Knublauch <holger@topquadrant.com>
>> <holger@topquadrant.com>
>> Cc:        RDF Data Shapes Working Group <public-data-shapes-wg@w3.org>
>> <public-data-shapes-wg@w3.org>
>> Date:        02/12/2015 08:08 PM
>> Subject:        Re: Two Standards ?
>> Sent by:        deanallemang@gmail.com
>> ------------------------------
>>
>>
>>
>> I have been talking about Shapes with my FIBO colleagues - we continue to
>> face the expressivity issues around OWL (role intersections and friendly
>> fire seem to come up a lot for us).  We are moving in to things like
>> SPIN/SWRL, and/or FIBO-RIF(a proposal that I worked on  last July that
>> moves everything into a subset of RIF) to solve our expressivity issues.
>> We are currently going to do all of this in Informative Annexes (as opposed
>> to normative recommendations), because we don't (yet) have a good standard
>> in which to write these things.
>>
>> An expressive shapes language, based on SPARQL, would satisfy our group's
>> needs quite well.
>>
>> I wonder a bit about the relationship between the two languages that
>> Holger proposes - is it important that we be able to define how a ShEx
>> shape corresponds to an LDOM definition?  Or are they being used in
>> completely different places?  I guess if we take the XSD/RelaxNG example,
>> there needn't be a deterministic relationship between them.
>>
>> Looking back, it seems to me that it would have been a good thing if
>> RELAX-NG had been done through the auspices of the W3C instead of OASIS.
>> As it stands now, it seems as if one has to choose one's standard
>> organization to support one's technology.  If we simply recognize that
>> there could be two different perspectives and develop both standards, we
>> could actually provide coherent (non-competitive) advice about when each
>> one should be used.  If we don't, and the other perspective has an
>> audience, we'll end up seeing it pursued in some other organization.  Ugh.
>>
>>
>> Prima facie, it would seem like we are doubling our work, but I don't
>> think that's the case. As Holger said, each group has done enough work now
>> to write up a coherent spec.  It would actually be *more* work to try to
>> reconcile them into a single Recommendation.
>>
>>
>> This situation seems to me to be a bit different from the profiles of
>> OWL, where we use the same words with different constraints on their
>> usage.  Here, we are solving parallel problems with different mechanisms.
>> Making two standards, that are well-informed by one another, seems like a
>> good idea to me.
>>
>>
>>
>> Dean
>>
>>
>>
>>
>>
>>
>> On Thu, Feb 12, 2015 at 7:25 PM, Holger Knublauch <
>> *holger@topquadrant.com* <holger@topquadrant.com>> wrote:
>> A random thought before the week end:
>>
>> Can this WG (please!) produce two separate standards?
>>
>> 1) An RDF vocabulary similar to the original LDOM proposal
>> 2) The ShEx Compact Syntax aiming at the data reuse scenarios
>>
>> We already have RDF Schema. We already have OWL. We would already have a
>> third language (LDOM or whatever). Why not have a forth language?
>>
>> The situation in very similar to XML Schema vs. DTD. vs RELAX-NG. They
>> all solve similar problems, but from different perspectives.
>>
>> We are currently trying to mix different paradigms together and risk
>> producing something that nobody will be happy with. People with OO
>> background will wonder what the fuzz is about this parallel structure
>> called "Shapes", raising the implementation costs and creating a mix of
>> parallel semantic webs. And ShEx people don't want to worry about the
>> interactions of the various triple models at all - instead have the ShExC
>> files live outside of the triple store. And that makes sense because even
>> if you introduce ldom:instanceShape to separate shapes from classes, you'd
>> still run into conflicts with other ShEx models that also happen to use
>> ldom:instanceShape. The only proper solution here is to not have triples in
>> the first place.
>>
>> Another constant source of conflict will be the role of SPARQL. The ShEx
>> camp seems to be more concerned about the balance of expressivity and
>> complexity, while the SPIN camp has plenty of use cases where expressivity
>> is the main concern. Furthermore, a SPIN-like LDOM can more easily be
>> combined with existing RDFS and OWL ontologies, filling gaps in that space.
>>
>> We have a handful of ShEx supporters in the WG. I am sure they could turn
>> their Member Submission into a formal spec quite rapidly. From an LDOM
>> point of view we have plenty of stuff already implemented, and I'd be happy
>> to wrestle and collaborate with anyone to flesh out the open details. The
>> Requirements document is already being split into "Property constraints"
>> and "Complex constraints", so both camps can harvest from the same catalog
>> of requirements. We can also share test cases and produce a small document
>> explaining how to map from one language to another. But the aforementioned
>> reasons and the endless discussions over the last half a year provide
>> plenty of arguments that justify why the WG chose to create two languages.
>>
>> Why would this separation of deliverables not work?
>>
>> Thanks,
>> Holger
>>
>>
>>
>>
>>
>
>