Re: Two Standards ?

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>
To:     Holger Knublauch <holger@topquadrant.com>
Cc:     RDF Data Shapes Working Group <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> 
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