Re: Shapes, Individuals, and Classes - OSLC Motivations

I still don't know what "custom" means here with respect to RDF.  As far as I 
can tell any bit of an ontology, or class, or property, or constraint, or 
shape could be called "custom".  Now it may be that within OSLC there is some 
notion of custom vs non-custom, but how can that notion be removed from OSLC 
so that it can be used elsewhere?

Similarly, the notions of "specification", "implementation", "project", etc., 
appear to me to be specific to OSLC, and particular to the design methodology 
you outline below, and using them to drive a spec could, I think, tie that 
spec quite closely to the design methodology.

As a contrast, here is what I believe should be used to say that classes and 
shapes/constraints are decoupled.

Definition:  Classes and shapes/constraints are decoupled if the specification 
can use different sets of shapes/constraints on the same class.  For example, 
if the specification permits the ontology
   ex:Person rdf:type rdfs:Class .
   ex:name rdf:type rdf:Property .
   ex:name rdfs:domain ex:Person .
to be used with the constraint set
   ex:Person < exists ex:name
(every person has a "known" value for its name)
or used with the constraint set
   ex:Person < all ex:name xsd:string
(all "known" names of people are strings)
then it will be said to allow the decoupling of constraints/shapes and classes.

A stronger notion would be that shapes/constraints are independent of classes. 
  This could be defined as:

Definition:  Classes and shapes/constraints are independent if some 
shapes/constraints do not use class membership in their definition.  For 
example, the following constraint is class-independent:
   exists ex:name < exactly 1 ex:name
(if something has a "known" name then it has exactly one "known" name)


On 11/06/2014 04:59 AM, Arthur Ryman wrote:
> Peter,
> OSLC defines specification for RDF representation of resources in several
> domains, e.g. Requirements, Quality, Change Management etc. A
> specification typically defines a class and several properties.
> Implementations are allowed to add new RDF properties but they don't
> necessarily introduce new RDF classes. Furthermore, within an
> implementation, users may add custom RDF properties on a
> project-by-project basis, but that doesn't change the RDF class. Therefore
> different projects use different Shapes but the Shapes only differ by RDF
> properties, not RDF classes. That is what I mean by decoupling Shapes and
> Classes.
> I will elaborate this on the wiki.
> _________________________________________________________
> Arthur Ryman
> Chief Data Officer
> SWG | Rational
> 905.413.3077 (phone) | 416.939.5063 (cell)
> IBM InterConnect 2015
> From:   "Peter F. Patel-Schneider" <>
> To:     Arthur Ryman/Toronto/IBM@IBMCA,,
> Date:   11/05/2014 05:27 PM
> Subject:        Re: Shapes, Individuals, and Classes - OSLC Motivations
> I'm still wondering what you think it means to decouple shapes and
> classes.
> The first motivation you provide is supported by both SPIN and OWL
> constraints.  I can't figure out what custom properties have to do with
> classes, or constraints, or shapes.  The behaviour you appear to be
> looking
> for in your second paragraph is also supported by both SPIN and OWL
> constraints.
> I had thought that this was ironed out at the Face-to-Face, but I guess
> not.
> peter
> On 11/05/2014 01:47 PM, Arthur Ryman wrote:
>> There are a few motivations for decoupling shapes and classes. One is
> that
>> the creation shape may be different than the update shape. Another has
> to
>> do with custom properties. I'll write up the following in the wiki.
>> OSLC supports an open content model for resources. It is common for
> tools
>> to add their own custom properties, and for projects within a tool to
> have
>> different user-defined properties. For example, consider a bug tracking
>> tool. Project A may add a custom property foo and project B may add bar.
>> All projects use the same RDF type for bug resources, e.g.
>> oslc_cm:ChangeRequest. However, the shape for resources in project A
>> differs for the shape for project B.
>> _________________________________________________________
>> Arthur Ryman
>> Chief Data Officer
>> SWG | Rational
>> 905.413.3077 (phone) | 416.939.5063 (cell)
>> IBM InterConnect 2015

Received on Thursday, 6 November 2014 17:14:43 UTC