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Re: ISSUE-595: Prov-xml subtyping needs to be marked in the document

From: Luc Moreau <l.moreau@ecs.soton.ac.uk>
Date: Tue, 20 Nov 2012 20:50:11 +0000
Message-ID: <EMEW3|a0416be8403cfaf0c97bf6907280cb78oAJKoh08l.moreau|ecs.soton.ac.uk|50ABED03.6070601@ecs.soton.ac.uk>
To: Stephan Zednik <zednis@rpi.edu>
CC: pgroth@gmail.com, Provenance Working Group <public-prov-wg@w3.org>
Hi Stephan,

On 20/11/12 18:26, Stephan Zednik wrote:
> The reason to allow defined prov types in the prov:type (PROV, not 
> XML) attribute would be to support multi-typing.
>
> A prov:Agent that is also a prov:Entity would be the most likely 
> scenario.  Luc mentioned a few others such as a Revision that is also 
> a Quotation and a Organization that is also a Person but I am not sure 
> those examples make sense.
>
> If all prov types are disjoint from any type they are not specified to 
> be a subtype of, then I agree we can leave prov:type for 
> domain-extended types only.  As it is now, I do not believe the 
> PROV-DM specifies any disjointness among defined PROV types and it 
> does say that the attribute prov:type can occur multiple times.

It's correct. There was no support for further disjointness axioms.

Luc

>
> --Stephan
>
> On Nov 20, 2012, at 8:58 AM, Paul Groth <pgroth@gmail.com 
> <mailto:pgroth@gmail.com>> wrote:
>
>> Hi,
>>
>> Why do we define the prov:type attribute to include the definitions 
>> of prov? Isn't it clear from the specs that there is subtyping. As an 
>> implementor I know that wasRevisionOf is a subtype of wasDerivedFrom?
>>
>> Thanks
>> Paul
>>
>>
>> On Tue, Nov 20, 2012 at 7:33 AM, Luc Moreau <L.Moreau@ecs.soton.ac.uk 
>> <mailto:L.Moreau@ecs.soton.ac.uk>> wrote:
>>
>>     Hi Stephan,
>>
>>     I think I concur with your conclusion: it may end up making
>>     tooling complex. Plus, the third way of writing things:
>>
>>     <proc:agent xsi:type="prov:Person" prov:id="ex:e"/>
>>
>>     Professor Luc Moreau
>>     Electronics and Computer Science
>>     University of Southampton
>>     Southampton SO17 1BJ
>>     United Kingdom
>>
>>     On 20 Nov 2012, at 01:09, "Stephan Zednik" <zednis@rpi.edu
>>     <mailto:zednis@rpi.edu>> wrote:
>>
>>     >
>>     >
>>     > On Nov 19, 2012, at 5:36 PM, Luc Moreau
>>     <L.Moreau@ecs.soton.ac.uk <mailto:L.Moreau@ecs.soton.ac.uk>> wrote:
>>     >
>>     >> Hi Stephan,
>>     >>
>>     >> It looks like a reasonable approach. Can we handle the case
>>     where a quotation is also a revision? Or a person also an
>>     organisation? ( not sure ths is all very meaningful, but this is
>>     valid).
>>     >
>>     > If I remember correctly that was one of the modeling issues
>>     that lead us to follow the PROV-N lead on sub-typing.
>>     >
>>     > The following is still valid
>>     >
>>     > <prov:person prov:id="ex:foo" >
>>     >  <prov:type xsi:type="xsd:QName">prov:Organization</prov:type>
>>     > </prov:person>
>>     >
>>     > I left prov:type as it was so all previous PROV-XML examples
>>     are still valid.   The 'a now b' examples from my previous email
>>     should be considered equivalent.  We now have two ways of
>>     declaring something is a person, revision, quotation, etc.
>>     whereas before we only had one.
>>     >
>>     > This seems like it would complicate tooling so I am not sure it
>>     as cut-and-dry the best direction as it would first seem.
>>     >
>>     > --Stephan
>>     >
>>     >>
>>     >> Professor Luc Moreau
>>     >> Electronics and Computer Science
>>     >> University of Southampton
>>     >> Southampton SO17 1BJ
>>     >> United Kingdom
>>     >>
>>     >> On 20 Nov 2012, at 00:02, "Stephan Zednik" <zednis@rpi.edu
>>     <mailto:zednis@rpi.edu>> wrote:
>>     >>
>>     >>> I have made notes in the PROV-XML Note document that examples
>>     of sub-typing are under discussion and may change in the future.
>>     >>>
>>     >>> https://dvcs.w3.org/hg/prov/rev/78a059d12dd2
>>     >>>
>>     >>> I have also created a copy of the existing schema with new
>>     complexTypes and elements for Person, Organization,
>>     SoftwareAgent, Collection, EmptyCollection, Plan, Revision,
>>     Quotation, and PrimarySource.
>>     >>>
>>     >>>
>>     https://dvcs.w3.org/hg/prov/raw-file/49d63187fb7f/xml/schema/prov.alt.xsd
>>     >>>
>>     >>> This is to address feedback raised on reliance on prov:type
>>     to express the above entity and derivation sub-typing.
>>     >>>
>>     >>> The new complex types use xs:extension to extend existing
>>     complexTypes.
>>     >>>
>>     >>> Two examples:
>>     >>>
>>     >>> <xs:complexType name="Person">
>>     >>>  <xs:complexContent>
>>     >>>    <xs:extension base="prov:Agent">
>>     >>>    </xs:extension>
>>     >>>  </xs:complexContent>
>>     >>> </xs:complexType>
>>     >>>
>>     >>> ...
>>     >>>
>>     >>> <xs:complexType name="Revision">
>>     >>>  <xs:complexContent>
>>     >>>    <xs:extension base="prov:Derivation">
>>     >>>      <!-- add any additional properties here -->
>>     >>>    </xs:extension>
>>     >>>  </xs:complexContent>
>>     >>> </xs:complexType>
>>     >>>
>>     >>> These changes lead to the following simplifications on our
>>     XML serialization:
>>     >>>
>>     >>> <prov:agent prov:id="ex:Paolo">
>>     >>>  <prov:type xsi:type="xsd:QName">prov:Person</prov:type>
>>     >>> </prov:agent>
>>     >>>
>>     >>> could now be modeled as
>>     >>>
>>     >>> <prov:person prov:id="ex:Paolo" />
>>     >>>
>>     >>> and
>>     >>>
>>     >>> <prov:wasDerivedFrom>
>>     >>>  <prov:generatedEntity prov:ref="tr:WD-prov-dm-20111215"/>
>>     >>>  <prov:usedEntity prov:ref="tr:WD-prov-dm-20111018"/>
>>     >>>  <prov:type xsi:type="xsd:QName">prov:Revision</prov:type>
>>     >>> </prov:wasDerivedFrom>
>>     >>>
>>     >>> could now be modeled as
>>     >>>
>>     >>> <prov:wasRevisionOf>
>>     >>>  <prov:generatedEntity prov:ref="tr:WD-prov-dm-20111215"/>
>>     >>>  <prov:usedEntity prov:ref="tr:WD-prov-dm-20111018"/>
>>     >>> </prov:wasRevisionOf>
>>     >>>
>>     >>> What does the group think of this approach?
>>     >>>
>>     >>> --Stephan
>>     >>>
>>     >>> On Nov 9, 2012, at 11:53 AM, Provenance Working Group Issue
>>     Tracker <sysbot+tracker@w3.org <mailto:sysbot%2Btracker@w3.org>>
>>     wrote:
>>     >>>
>>     >>>> ISSUE-595: Prov-xml subtyping needs to be marked in the document
>>     >>>>
>>     >>>> http://www.w3.org/2011/prov/track/issues/595
>>     >>>>
>>     >>>> Raised by:
>>     >>>> On product:
>>     >>>>
>>     >>>>
>>     >>>>
>>     >>>>
>>     >>>>
>>     >>>>
>>     >>>
>>     >>>
>>     >>
>>     >>
>>     >
>>
>>
>

-- 
Professor Luc Moreau
Electronics and Computer Science   tel:   +44 23 8059 4487
University of Southampton          fax:   +44 23 8059 2865
Southampton SO17 1BJ               email: l.moreau@ecs.soton.ac.uk
United Kingdom                     http://www.ecs.soton.ac.uk/~lavm
Received on Tuesday, 20 November 2012 20:51:16 GMT

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