Re: Shapes, Individuals, and Classes - OSLC Motivations

* Arthur Ryman <ryman@ca.ibm.com> [2014-11-12 08:45-0500]
> Yes, It should have gone to the list.

my fault. i figured we could go offlist to work this out and just
reply to an earlier message to relay the resolution.

> _________________________________________________________
> Arthur Ryman
> Chief Data Officer
> SWG | Rational
> 905.413.3077 (phone) | 416.939.5063 (cell)
> IBM InterConnect 2015
> 
> 
> 
> 
> From:   "Peter F. Patel-Schneider" <pfpschneider@gmail.com>
> To:     Arthur Ryman/Toronto/IBM@IBMCA, "Eric Prud'hommeaux" 
> <eric@w3.org>, 
> Date:   11/12/2014 08:21 AM
> Subject:        Re: Shapes, Individuals, and Classes - OSLC Motivations
> 
> 
> 
> Did you mean to not send this reply to the working group?
> 
> peter
> 
> 
> On 11/12/2014 05:14 AM, Arthur Ryman wrote:
> > Eric,
> >
> > Thanks. Yes, Peter is right. The terms use lexical forms. So we need to
> > refer to the datatype value space explicitly when defining the semantics
> > of constraints. This does not mean that we need to go beyond the RDF 
> spec
> > and depend on RDFS or OWL.
> > _________________________________________________________
> > Arthur Ryman
> > Chief Data Officer
> > SWG | Rational
> > 905.413.3077 (phone) | 416.939.5063 (cell)
> > IBM InterConnect 2015
> >
> >
> >
> >
> > From:   "Eric Prud'hommeaux" <eric@w3.org>
> > To:     Arthur Ryman/Toronto/IBM@IBMCA,
> > Cc:     "Peter F. Patel-Schneider" <pfpschneider@gmail.com>
> > Date:   11/12/2014 02:05 AM
> > Subject:        Re: Shapes, Individuals, and Classes - OSLC Motivations
> >
> >
> >
> > Cc- Arnaud Le Hors <lehors@us.ibm.com>, public-data-shapes-wg@w3.org
> >
> > * Arthur Ryman <ryman@ca.ibm.com> [2014-11-11 20:28-0500]
> >> Peter,
> >>
> >> One of us is misinterpreting the specs. I'd like others to weigh in.
> >
> > The abstract syntax defines RDF terms.
> >    <
> > http://www.w3.org/TR/2014/REC-rdf11-concepts-20140225/#section-rdf-graph
> >
> > A BNF would look like:
> > [[
> >    Dataset: DefaultGraph NamedGraph*
> >    DefaultGraph: Graph
> >    NamedGraph: GraphLabel Graph
> >    GraphLabel: NonLiteral
> >    Graph: Triple*
> >    Triple: S P O
> >    S: NonLiteral
> >    P: IRI
> >    O: Literal | NonLiteral
> >    NonLiteral: IRI | BNode
> >    Literal: LangTagged | NonLangTagged
> >    NonLangTagged: LexicalForm DatatypeIRI
> >    LangTagged: LexicalForm DatatypeIRI LangTag # |DatatypeIRI=xs:string
> >    DatatypeIRI: IRI
> >    IRI: per <http://www.w3.org/TR/rdf11-concepts/#dfn-iri>
> >    BNode: per <http://www.w3.org/TR/rdf11-concepts/#dfn-blank-node>
> >    LexicalForm: per <
> http://www.w3.org/TR/rdf11-concepts/#dfn-lexical-form>
> >    LangTag: per <
> > http://www.w3.org/TR/rdf11-concepts/#dfn-language-tagged-string>
> > ]]
> > ? <http://www.w3.org/mid/20131205102850.GB25415@w3.org>
> >
> > The only one of those #dfn- thingies that normalizes is the one for
> > language string, so
> >              "ab"@EN == "ab"@en.
> > <http://a.example/> != <http://A.example/>
> >     "1"^^xsd:integer != "01"^^xsd:integer
> >
> > SPARQL's operators use XPath functions, which in tern establish some
> > equivalences, e.g. 01 == 1. See
> > <http://www.w3.org/mid/20141110174535.GE18442@w3.org>
> >
> >
> >> Arnaud, Perhaps we could put this on the agenda for tomorrow.
> >> _________________________________________________________
> >> Arthur Ryman
> >> Chief Data Officer
> >> SWG | Rational
> >> 905.413.3077 (phone) | 416.939.5063 (cell)
> >> IBM InterConnect 2015
> >>
> >>
> >>
> >>
> >> From:   "Peter F. Patel-Schneider" <pfpschneider@gmail.com>
> >> To:     Arthur Ryman/Toronto/IBM@IBMCA,
> >> Cc:     "Eric Prud'hommeaux" <eric@w3.org>, 
> public-data-shapes-wg@w3.org
> >> Date:   11/11/2014 07:59 PM
> >> Subject:        Re: Shapes, Individuals, and Classes - OSLC Motivations
> >>
> >>
> >>
> >> You can disagree all you want, but "1"^^xsd:integer and
> > "01"^^xsd:integer
> >> do
> >> indeed represent different nodes in any RDF graph.  To see this all you
> >> have
> >> to look at is the RDF Concepts and Abstract Syntax
> >> http://www.w3.org/TR/2014/REC-rdf11-concepts-20140225/ Section 3.3,
> > which
> >> talks about literal term equality, and Section 3.1, which says that the
> >> triples of RDF objects can be literals.
> >>
> >> Neither datatypes nor the RDF model theory nor what an RDF literal
> >> represents
> >> affect this aspect of RDF graphs.
> >>
> >> peter
> >>
> >>
> >>
> >> On 11/11/2014 02:00 PM, Arthur Ryman wrote:
> >>> Peter,
> >>>
> >>> I disagree with your assertion that "1"^^xsd:integer and
> >> "01"^^xsd:integer
> >>> represent different RDF nodes. Please refer to [1] and [2]
> >>>
> >>> A datatype consists of a lexical space, and value space, and a
> >>> lexical-to-value mapping. Several strings in the lexical space may map
> >
> >> to
> >>> the same element of the value space.  An RDF literal that includes a
> >>> datatype URI represents the value, i.e. the lexical-to-value mapping
> > is
> >>> applied to the lexical string.
> >>>
> >>> [1] http://www.w3.org/TR/rdf11-concepts/#section-Datatypes
> >>> [2] http://www.w3.org/TR/rdf11-mt/#literals-and-datatypes
> >>> _________________________________________________________
> >>> Arthur Ryman
> >>> Chief Data Officer
> >>> SWG | Rational
> >>> 905.413.3077 (phone) | 416.939.5063 (cell)
> >>> IBM InterConnect 2015
> >>>
> >>>
> >>>
> >>>
> >>> From:   "Peter F. Patel-Schneider" <pfpschneider@gmail.com>
> >>> To:     Arthur Ryman/Toronto/IBM@IBMCA, "Eric Prud'hommeaux"
> >>> <eric@w3.org>,
> >>> Cc:     public-data-shapes-wg@w3.org
> >>> Date:   11/10/2014 10:54 AM
> >>> Subject:        Re: Shapes, Individuals, and Classes - OSLC
> > Motivations
> >>>
> >>>
> >>>
> >>> RDF graphs are defined without respect to XML datatypes.  For example,
> >>> "1"^^^xsd:integer and "01"^^xsd:integer are different as far as RDF
> >> graphs
> >>> are
> >>> concerned.
> >>>
> >>> Of course, there is a close relationship between these two literals,
> > but
> >>> that
> >>> is (mostly) defined in the RDF semantics.
> >>>
> >>> So is it then the case that OSLC goes beyond RDF graphs?
> >>>
> >>> peter
> >>>
> >>>
> >>> On 11/10/2014 07:38 AM, Arthur Ryman wrote:
> >>>> Eric,
> >>>>
> >>>> Yes. RDF includes the built-in XML datatypes.
> >>>> _________________________________________________________
> >>>> Arthur Ryman
> >>>> Chief Data Officer
> >>>> SWG | Rational
> >>>> 905.413.3077 (phone) | 416.939.5063 (cell)
> >>>> IBM InterConnect 2015
> >>>>
> >>>>
> >>>>
> >>>>
> >>>> From:   "Eric Prud'hommeaux" <eric@w3.org>
> >>>> To:     "Peter F. Patel-Schneider" <pfpschneider@gmail.com>,
> >>>> Cc:     Arthur Ryman/Toronto/IBM@IBMCA, public-data-shapes-wg@w3.org
> >>>> Date:   11/07/2014 08:46 AM
> >>>> Subject:        Re: Shapes, Individuals, and Classes - OSLC
> > Motivations
> >>>>
> >>>>
> >>>>
> >>>> * Peter F. Patel-Schneider <pfpschneider@gmail.com> [2014-11-06
> >>>> 20:36-0800]
> >>>>> So your view is that all that counts is the graph?  Nothing about
> >>>>> datatypes, or RDF, or RDFS?
> >>>>
> >>>> I suspect that OSLC wants datatypes, noting that Resource Shapes has
> >>>> an oslc:valueType predicate for identifying the datatype of a
> > literal.
> >>>>
> >>>>      
> http://www.w3.org/Submission/2014/SUBM-shapes-20140211/#valueType
> >>>>
> >>>>
> >>>>> peter
> >>>>>
> >>>>>
> >>>>> On 11/06/2014 12:01 PM, Arthur Ryman wrote:
> >>>>>> Peter,
> >>>>>>
> >>>>>> Commenting on your proposed wording of how to express the
> >> "decoupling"
> >>>>>> requirement. I'd go further and demote the notion of class to being
> >>>> more
> >>>>>> like just another property and view the shape/constraints as
> > applying
> >>>> to
> >>>>>> the RDF representation of an information resource, i.e. to a set of
> >>>>>> triples (aka an RDF graph). Some of the triples will have rdf:type
> > as
> >>>> the
> >>>>>> predicate and those triples are useful for locating certain subject
> >>>> nodes
> >>>>>> that we want to say more things about, e.g that they are the
> > subjects
> >>>> of
> >>>>>> triples that have certain other predicates, etc.
> >>>>>> _________________________________________________________
> >>>>>> Arthur Ryman
> >>>>>> Chief Data Officer
> >>>>>> SWG | Rational
> >>>>>> 905.413.3077 (phone) | 416.939.5063 (cell)
> >>>>>> IBM InterConnect 2015
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>> From:   "Peter F. Patel-Schneider" <pfpschneider@gmail.com>
> >>>>>> To:     Arthur Ryman/Toronto/IBM@IBMCA,
> >>>>>> Cc:     public-data-shapes-wg@w3.org
> >>>>>> Date:   11/06/2014 12:14 PM
> >>>>>> Subject:        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)
> >>>>>>
> >>>>>>
> >>>>>> peter
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>> 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" <pfpschneider@gmail.com>
> >>>>>>> To:     Arthur Ryman/Toronto/IBM@IBMCA,
> >> public-data-shapes-wg@w3.org,
> >>>>>>> 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
> >>>>>>>>
> >>>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>
> >>>>
> >>>
> >>>
> >>>
> >>
> >>
> >>
> >
> 
> 
> 

-- 
-ericP

office: +1.617.599.3509
mobile: +33.6.80.80.35.59

(eric@w3.org)
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Received on Wednesday, 12 November 2014 14:17:05 UTC