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Re: PROV comments from Clark&Parsia

From: Timothy Lebo <lebot@rpi.edu>
Date: Mon, 28 Jan 2013 10:01:04 -0500
Cc: W3C provenance WG <public-prov-wg@w3.org>
Message-Id: <3BB92A69-9D33-42B5-8B2F-0C524585E86A@rpi.edu>
To: Luc Moreau <L.Moreau@ecs.soton.ac.uk>
Tracker, this is Luc's comment on

ISSUE-617

-Tim



On Jan 24, 2013, at 9:32 AM, Luc Moreau <L.Moreau@ecs.soton.ac.uk> wrote:

> Hi Paul, all,
> 
> It would be good to discuss this issue today at the teleconference.
> 
> I personally think the hierarchy of classes rooted at prov:Influence is an intrinsic aspect
> of the design of prov-o. The group recently decided to create a parallel hierarchy of
> subproperties rooted at prov:influence. These hierarchies happen to be an implementation of constraint
> Inference 15 (influence-inference). Good, it's a bonus.
> 
> Luc
> 
> 
> 
> 
> On 23/01/2013 17:24, Evren Sirin 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
>>>     
>>   
> 
> -- 
> 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 Monday, 28 January 2013 15:01:57 UTC

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