W3C home > Mailing lists > Public > public-prov-wg@w3.org > April 2012

Re: PROV-ISSUE-136 (collection-functional): Collection not stated as functional [Data Model]

From: Stian Soiland-Reyes <soiland-reyes@cs.manchester.ac.uk>
Date: Wed, 25 Apr 2012 10:08:04 +0100
Message-ID: <CAPRnXtkizDafJaDDEKVRbCqVdmv9OVNtdPpaCQDb=VkSVdvuyw@mail.gmail.com>
To: Provenance Working Group WG <public-prov-wg@w3.org>
I have closed this issue, as PROV-CONSTRAINTS now says: "PROV-DM does
not provide an interpretation for descriptions that consist of two (or
more) insertion, removal, membership relations that result in the same
collection."


On Wed, Feb 22, 2012 at 15:49, Stian Soiland-Reyes
<soiland-reyes@cs.manchester.ac.uk> wrote:
> This issue is still open, as DM is currently almost contradicting
> itself on functionality. I've marked this as an issue in [1]:
>
>
>> One can have multiple assertions regarding the state of a collection following a set of insertions, for example:
> CollectionAfterInsertion(c2,c1, k1, v1)
> CollectionAfterInsertion(c2,c1, k2, v2)
> ...
> This is interpreted as " c2 is the state that results from inserting
> (k1, v1), (k2, v2) etc. into c1
>
>
>> Both relations are functional, in the sense that they represent a state change following a unique insertion/removal operation (or a unique set of them). Thus, from the pair of assertions:
> CollectionAfterInsertion(c, c1, k1, v1)
> CollectionAfterInsertion(c, c2, k2, v2)
> one can infer: c1==c2, k1==k2, v1==v2, because one cannot have two
> different derivations for the same final collection state.
>
>
> We have to decide on one of these. My feeling is that it should be
> functional on all parameters, because otherwise the open-world
> assumption means there could also be an unknown additional
> insertions/deletions between c1 and c. (This touches on ISSUE-137
> [2]).
>
>
> However, this then leaves ISSUE-138 open for how to represent multiple
> insertions/removal. See separate email about this.
>
>
>
>
> [1] http://dvcs.w3.org/hg/prov/raw-file/tip/model/ProvenanceModel.html#record-Collection
> [2] http://www.w3.org/2011/prov/track/issues/137
> [3] http://www.w3.org/2011/prov/track/issues/138
>
>
>
> On Sun, Oct 30, 2011 at 00:18, Provenance Working Group Issue Tracker
> <sysbot+tracker@w3.org> wrote:
>>
>> PROV-ISSUE-136 (collection-functional): Collection not stated as functional [Data Model]
>>
>> http://www.w3.org/2011/prov/track/issues/136
>>
>> Raised by: Stian Soiland-Reyes
>> On product: Data Model
>>
>> http://www.w3.org/TR/prov-dm/#expression-Collection introduces relations for expressing collection addition by using three statements
>>
>>  wasAddedTo_Coll(c2,c1)
>>  wasAddedTo_Key(c2,k1)
>>  wasAddedTo_Entity(c2,e1)
>>
>> Saying that c2 is the content of c1 - but with e1 added under the key k1.
>>
>> It is not stated that the relations are functional - thus it would be valid to also say *for the same collection c2*:
>>
>>  wasAddedTo_Key(c2,k2)
>>  wasAddedTo_Entity(c2,e2)
>>
>>
>> But now assuming order of assertions in PROV-ASN don't matter - we don't know if it is (k2,e2) and (k1,e1) that was added, alternatively (k1,e2) and (k2,e1).
>>
>>
>> My rough interpretation is that these assertions are meant to be functional - so that you can only add one key->entity at a time. If this is true, it should be stated in PROV-DM.
>>
>> If it is not - then a different way to associate the key to the value is needed, like a new "CollectionEntry" entity with attributes "key:,  "value" and possibly "collection".
>>
>>
>>
>
>
>
> --
> Stian Soiland-Reyes, myGrid team
> School of Computer Science
> The University of Manchester



-- 
Stian Soiland-Reyes, myGrid team
School of Computer Science
The University of Manchester
Received on Wednesday, 25 April 2012 09:08:58 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Thursday, 26 April 2012 13:07:03 GMT