Re: Two Standards ?

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>
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
>
>
>