- From: Anthony Moretti <anthony.moretti@gmail.com>
- Date: Wed, 6 Jun 2018 14:50:09 -0700
- To: pfpschneider@gmail.com
- Cc: richard.wallis@dataliberate.com, public-schemaorg@w3.org
- Message-ID: <CACusdfSg1=ebVo+LmQq5d4H4=BVDUctsossGZgyC2sbu_aekmw@mail.gmail.com>
Peter, when you say "roles fall outside the purview of OWL" is it possible
that Role should be a subtype of Event, thus requiring no special
treatment? I say that because individual roles have potential start and end
dates.
If you continue that thinking you end up with several types that might be
considered subtypes of Event:
Event
Action
Course
Role
Offer
Parcel delivery
Trip
Anthony
On Wed, Jun 6, 2018 at 7:42 AM Peter F. Patel-Schneider <
pfpschneider@gmail.com> wrote:
> OK, it appears that you are trying to produce an OWL ontology that would
> accept schema.org documents that would accept unexceptional schema.org
> documents (under some loose definition of what makes an unexceptional
> schema.org document).
>
>
> But you are running up against problems with "strings as things" and
> Roles.
>
>
> Look at about and subjectOf. Any use of a string as a value for about is
> going to make that string an instance of two OWL Classes (the range of
> about,
> which includes Text, and the domain of subjectOf, which doesn't). This is
> not
> permissible in OWL.
>
>
> Using a role as a value for subjectOf will make the role node an instance
> of
> the domain of about, which doesn't include Role. Roles fall outside the
> purview of OWL.
>
>
> What I think has to be done for "strings as things" is to preprocess them
> as
> an anonymous node with the string as the value of some description
> property.
> Roles need to be short-circuited and the role values eliminated. If the
> role
> values are to be retained then some sort of fancy reification has to be
> introduced.
>
>
> But a lot of this is guesswork, as it is unclear just what "strings as
> things"
> and Roles mean in schema.org. (I haven't looked closely at the use of
> URLs
> as stand-ins for objects but my guess is that that is similar to "strings
> as
> things".)
>
>
>
> OWL makes a distinction between object and data values, and this
> distinction
> has to be carried through to the ontology, where there are classes and
> datatypes. As far as I can tell Text should be a datatype.
>
>
>
>
> peter
>
>
>
> On 06/06/2018 07:09 AM, Richard Wallis wrote:
> > Just the fresh pair of experienced eyes I needed! - Thanks @Thomas
> >
> > @Danbri - not “wasting a lot of time agonising", in simple terms I’m just
> > [selfishly] trying to get a useful version to load into Protégé and
> > hopefully helping a few others at the same time.
> >
> > @Peter thanks for your thoughtful questions. As you can see from the
> above
> > the prime simple objective is to get it visible in Protégé. Beyond
> that, it
> > is to capture the class and property hierarchy of Schema.org including
> > the multiple domain/ranges of properties defined [In Schema.org] using
> > domainIncludes & rangeIncludes, in a way that a tool like Protégé can
> cope
> > with. As for ranges, it includes the assumption that properties, in
> > addition to the defined range(s), also have Text, URL, and Role included
> in
> > their range.
> >
> > Once I’ve done it, I want to add the simple generating code to the Schema
> > scripts run at release time so that it can be kept up to date.
> >
> >
> > ~Richard.
> >
> > Richard Wallis
> > Founder, Data Liberate
> > http://dataliberate.com
> > Linkedin: http://www.linkedin.com/in/richardwallis
> > Twitter: @rjw
> >
> > On 6 June 2018 at 14:45, Peter F. Patel-Schneider <
> pfpschneider@gmail.com
> > <mailto:pfpschneider@gmail.com>> wrote:
> >
> > It's hard to say much about the file without knowing what it is
> supposed to
> > capture.
> >
> >
> > It is supposed to capture the class and property hierarchy and
> property
> > restrictions or schema.org <http://schema.org>, but not necessarily
> in a
> > form compatible with RDFS
> > or OWL?
> >
> >
> > Is it supposed to faithfully encode the model theory of schema.org
> > <http://schema.org> in OWL?
> > If so, where is the document for this theory?
> >
> >
> > Is it supposed to capture "strings as things" or Roles?
> >
> >
> > How does it view property domains and ranges? As axioms? As strict
> > constraints? As soft constraints?
> >
> >
> > I would also move from rdf/xml to turtle, which is easier to write
> and
> > easier
> > to read.
> >
> >
> > peter
> >
> >
> >
> > On 06/06/2018 05:05 AM, Richard Wallis wrote:
> > > Calling folks with more OWL experience than me!
> > >
> > > The schema.org <http://schema.org> <http://schema.org> site has
> an OWL
> > definition file that has
> > > not been maintained since April 2014:
> http://schema.org/docs/schemaorg.owl <http://schema.org/docs/schemaorg.owl
> >.
> > > Also the structure and syntax of the file needs some attention.
> > >
> > > To help with the occasional questions about accessing processable
> > > representations of the vocabulary; to attempt to close an issue
> (#1611
> > > <https://github.com/schemaorg/schemaorg/issues/1611
> > <https://github.com/schemaorg/schemaorg/issues/1611>>); and to help
> with a
> > > personal project, I have had a look at producing an up to date,
> improved,
> > > maintainable version of the file.
> > >
> > > My first attempt can be downloaded/viewed
> > > here: https://s3.amazonaws.com/rjwPublicData/public/schemaorg.owl
> > <https://s3.amazonaws.com/rjwPublicData/public/schemaorg.owl>
> > >
> > > I am looking for comments, suggestions, and help around a few
> aspects of
> > > this work in progress:
> > >
> > > * Is it generally ‘a good owl file’
> > >
> > > * Should it contain more/less info about the vocabulary and its
> terms
> > >
> > > * Specifically with reference to domainIncludes and rangeInclude
> -
> > mapped
> > > to rdfs:domain & rdfs:range with owl:unionOfcollections:
> > >
> > > o Is this the best/only way to represent multiple domain &
> > ranges for
> > > an objectproperty?
> > >
> > > o Have I got the syntax correct?
> > >
> > > * Several people use Protégé <https://protege.stanford.edu/> as
> a
> > tool for
> > > this kind of effort - I am trying to identify what syntax,
> will enable
> > > this tool to recognise the multiple domain/ranges when
> importing
> > this file.
> > >
> > > If anyone out there with more OWL experience than me (not
> difficult),
> > could
> > > spend a few minutes taking a look at this and commenting, it would
> be
> > > greatly appreciated.
> > >
> > > ~Richard
> > >
> > > Richard Wallis
> > > Founder, Data Liberate
> > > http://dataliberate.com
> > > Linkedin: http://www.linkedin.com/in/richardwallis
> > <http://www.linkedin.com/in/richardwallis>
> > > Twitter: @rjw
> >
> >
> >
>
>
>
Received on Thursday, 7 June 2018 00:09:03 UTC