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Re: PROV comments from Clark&Parsia

From: Paul Groth <p.t.groth@vu.nl>
Date: Wed, 23 Jan 2013 17:27:04 +0100
Message-ID: <CAJCyKRpU2HYSR3rvmk1pRxeErfw-SydLw-aHJB=dTXzRAGDB7g@mail.gmail.com>
To: Evren Sirin <evren@clarkparsia.com>
Cc: "public-prov-comments@w3.org" <public-prov-comments@w3.org>, Héctor Pérez-Urbina <hector@clarkparsia.com>
Evren,

Thanks for the clarification, we'll take a look.

Thanks
Paul


On Wed, Jan 23, 2013 at 5:24 PM, Evren Sirin <evren@clarkparsia.com> wrote:

> Hi Paul,
>
> The short summary is we are fine with all the responses from the WG
> except the response for "ISSUE-611 (comments on prov-o)" for which we
> request more clarification. See below for more details.
>
> On Mon, Jan 21, 2013 at 4:56 AM, Paul Groth <p.t.groth@vu.nl> wrote:
> > Dear Evren,
> >
> > First, thanks for your interest in PROV. We are really excited that
> Clark &
> > Parsia are looking at implementing PROV within Stardog.
> >
> > The working group has looked at the issues you raised and produced
> replies.
> > We divided your comment into four parts. You'll find the responses
> linked to
> > below.
> >
> > - ISSUE-611 (comments on prov-constraints)
>
> These changes address our concerns.
>
> >
> > - ISSUE-611 (PROV-CONSTRAINT Test Cases)
>
> We are happy with the changes to the tests and the explanation.
>
> >
> > - ISSUE-611 (comments on prov-o)
>
> Our comment was not regarding encoding of the constraints in OWL
> (which is not possible to do completely anyway) but about encoding the
> inferences in OWL. Right now, it looks like some of the inferences
> from PROV Constraints document is included in PROV-O. Specifically,
> Inference 15 (influence-inference) [1] and Inference 20
> (specialization-alternate-inference) [2] are included in PROV-O as
> subPropertyOf axioms. But other inferences defined in this document
> are not included in PROV-O which is a little confusing. For example,
> Inference 12 (revision-is-alternate-inference) [3] suggests another
> subPropertyOf relation (wasRevisionOf subPropertyOf alternateOf) but
> this is not in PROV-O. If the WG chooses to encode some of the
> inferences in PROV-O but not others, we would like to understand the
> rationale behind this decision.
>
> >
> > - ISSUE-611 (Test cases for other specifications)
>
> Our comment was regarding test cases that test different aspects of
> PROV specification other than validation such as inferences. Analogous
> to OWL test cases where there are tests of (in)consistency and
> (non-)entailment, there could be PROV test cases for just testing
> entailments (transitivity, inverses, etc. as defined in the PROV
> constraints document) in addition to the current tests that check
> (in)validity. Having said that, this comment is meant to be a
> recommendation for additional future tests and we are fine with the
> current set of tests.
>
> >
> > We hope these address your concerns. If you could do us a favour and
> > acknowledge that these responses either address concerns or do not.
>
> Best,
> Evren
>
> [1] http://www.w3.org/TR/prov-constraints/#influence-inference
> [2]
> http://www.w3.org/TR/prov-constraints/#specialization-alternate-inference
> [3] http://www.w3.org/TR/prov-constraints/#revision-is-alternate-inference
>
> >
> > Thanks again for your detailed comments,
> > Paul
> >
> >
> >
> >
> >
> >
> >
> >
> > On Fri, Jan 4, 2013 at 6:23 PM, Evren Sirin <evren@clarkparsia.com>
> wrote:
> >>
> >> Hi all,
> >>
> >> We are working towards supporting PROV inferences and constraints in
> >> our RDF database Stardog [1]. Below are some comments about PROV
> >> specification documents that we identified while working on our
> >> implementation.
> >>
> >> * PROV Constraints
> >>
> >> 1. The flow control arrows in Figure 1 seem to be backwards.
> >> 2. Definition 2.1 seems to be missing the id on the right-hand side.
> >> 3. Since uniqueness constraints are ‘applied’ and can derive new
> >> atoms, it is misleading to call them constraints. The same applies to
> >> typing constraints.
> >> 4. The definition of enforcement of uniqueness constraints states one
> >> should apply the resulting substitution to the whole PROV instance.
> >> However, the scope of the variables is not sets of rules.
> >> 5. Inference 9 (wasStartedBy-inference) should be: IF
> >> wasStartedBy(_id; _a,e1,a1,_t,_attrs), THEN there exist _gen and _t1
> >> such that wasGeneratedBy(_gen; e1,a1,_t1,[]).
> >> 6. Inference 10 (wasEndedBy-inference) should be: IF wasEndedBy(_id;
> >> _a,e1,a1,_t,_attrs), THEN there exist _gen and _t1 such that
> >> wasGeneratedBy(_gen; e1,a1,_t1,[]).
> >> 7. Inference 15.4 should be: IF wasStartedBy(id; a2,e,_a1,_t,attrs)
> >> THEN wasInfluencedBy(id; a2, e, attrs).
> >> 8. Inference 15.7 should be: IF wasDerivedFrom(id; e2, e1, _a, _g, _u,
> >> attrs) THEN wasInfluencedBy(id; e2, e1, attrs).
> >> 9. Constraint 56 should be: IF hadMember(c,e) and
> >> 'prov:EmptyCollection' ∈ typeOf(c) THEN INVALID.
> >>
> >> * PROV-O
> >>
> >> PROV Ontology contains several axioms for inferencing but it does not
> >> cover all the inferences described in the PROV constraints document
> >> even though these inferences can be encoded in OWL in a
> >> straightforward way. We think these inferences are useful not just for
> >> validation but also for querying PROV documents. For this reason, we
> >> believe these inferences should be included in PROV-O.
> >>
> >> Here are some example OWL axioms encoding some of the inferences from
> >> PROV constraints document:
> >>
> >> # Inference 16 (alternate-reflexive)
> >> # IF entity(e) THEN alternateOf(e,e).
> >>
> >> :Entity
> >>    rdfs:subClassOf [
> >>        a owl:Restriction ;
> >>        owl:hasSelf true ;
> >>        owl:onProperty :alternateOf
> >>    ] .
> >>
> >> # Inference 17 (alternate-transitive)
> >> # IF alternateOf(e1,e2) and alternateOf(e2,e3) THEN alternateOf(e1,e3).
> >>
> >> :alternateOf a owl:TransitiveProperty .
> >>
> >> # Inference 18 (alternate-symmetric)
> >> # IF alternateOf(e1,e2) THEN alternateOf(e2,e1).
> >>
> >> :alternateOf a owl:SymmetricProperty .
> >>
> >> # Inference 19 (specialization-transitive)
> >> # IF specializationOf(e1,e2) and specializationOf(e2,e3) THEN
> >> specializationOf(e1,e3).
> >>
> >> :specializationOf a owl:TransitiveProperty .
> >>
> >> # Inference 20 (specialization-alternate-inference)
> >> # IF specializationOf(e1,e2) THEN alternateOf(e1,e2).
> >>
> >> :specializationOf rdfs:subPropertyOf owl:TransitiveProperty .
> >>
> >> * PROV-CONSTRAINTS Test Cases
> >>
> >> We appreciate as implementers the PROV-Constraints test suite. We
> >> would like to see test suites for the other operational parts of PROV,
> >> in particular for testing inferences separate from validation. This
> >> request arises from our general belief that interoperability with a
> >> formal spec is typically less high than interoperability with a formal
> >> spec *and* an executable test suite. Test suites are invaluable for
> >> implementations. Further, while we would like to see the test suites
> >> be made normative parts of PROV (since that gives a nice algorithm for
> >> resolving disagreements between spec test and test suite (i.e., tie
> >> goes to the test suite)), we would prefer non-normative test suites to
> >> no test suites at all.
> >>
> >> We identified the following issues in the following RDF test cases:
> >>
> >> * prov-o-class-Invalidation-PASS.ttl: At line 37, there are repeated
> >> semi-colons ‘;;’ which is invalid according to the Turtle grammar
> >> (neither [2] nor [3] seems to allow this).
> >> * prov-o-class-Collection-PASS.ttl: Invalid xsd:dateTime literals
> >> missing minutes and timezone identifier.
> >> * prov-o-property-hadMember-PASS.ttl: Invalid xsd:dateTime literals
> >> missing minutes and timezone identifier.
> >> * ordering-association2-PASS-c47.ttl: This test is marked PASS but it
> >> is inconsistent because the individual ex:ag is an instance of
> >> disjoint classes prov:Entity and prov:Activity.
> >> * prov-o-property-qualifiedCommunication-PASS.ttl: This test is marked
> >> PASS but it is inconsistent because the individual
> >> :writing-celebrity-gossip is an instance of prov:Activity but uses the
> >> property prov:wasAttributedTo whose domain is the disjoint class
> >> prov:Entity. Same argument is also true for the individual
> >> :voicemail-interception.
> >> * prov-o-property-qualifiedRevision-PASS.ttl: This test is marked PASS
> >> but it is inconsistent because the individual :draft2 is an instance
> >> of prov:Entity but uses the property prov:wasAssociatedWith whose
> >> domain is the disjoint class prov:Activity.
> >>
> >> We think following tests should not have been included in
> >> rdf-tests.txt because the invalid PROV-N constructs cannot be
> >> expressed in RDF and thus their RDF representation is valid:
> >>            unification-association-f4-FAIL-c23.ttl
> >>            unification-association-f5-FAIL-c23.ttl
> >>            unification-derivation-f1-FAIL-c23.ttl
> >>            unification-derivation-f2-FAIL-c23.ttl
> >>            unification-derivation-f3-FAIL-c23.ttl
> >>            unification-derivation-f4-FAIL-c23.ttl
> >>
> >> Best,
> >> Evren
> >>
> >> [1] http://stardog.com/
> >> [2] http://www.w3.org/TeamSubmission/turtle/#sec-grammar
> >> [3] http://www.w3.org/TR/turtle/#sec-grammar
> >>
> >>
> >> --
> >> Evren Sirin
> >> CTO
> >> Clark & Parsia, LLC
> >> http://clarkparsia.org
> >>
> >
> >
> >
> > --
> > --
> > Dr. Paul Groth (p.t.groth@vu.nl)
> > http://www.few.vu.nl/~pgroth/
> > Assistant Professor
> > - Knowledge Representation & Reasoning Group |
> >   Artificial Intelligence Section | Department of Computer Science
> > - The Network Institute
> > VU University Amsterdam
>



-- 
--
Dr. Paul Groth (p.t.groth@vu.nl)
http://www.few.vu.nl/~pgroth/
Assistant Professor
- Knowledge Representation & Reasoning Group |
  Artificial Intelligence Section | Department of Computer Science
- The Network Institute
VU University Amsterdam
Received on Wednesday, 23 January 2013 16:27:33 GMT

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