- From: Arthur Ryman <ryman@ca.ibm.com>
- Date: Wed, 12 Nov 2014 08:45:05 -0500
- To: "Peter F. Patel-Schneider" <pfpschneider@gmail.com>, public-data-shapes-wg@w3.org
- Cc: "Eric Prud'hommeaux" <eric@w3.org>
Yes, It should have gone to the list. _________________________________________________________ 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 >>>>>>>> >>>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>> >>>>>> >>>>>> >>>>> >>>> >>> >>> >>> >> >> >> >
Received on Wednesday, 12 November 2014 13:45:38 UTC