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Re: PROV-ISSUE-638 (TomDN): Notation of set of key-value pairs in contraints of PROV Dictionary [PROV-DICTIONARY]

From: Tom De Nies <tom.denies@ugent.be>
Date: Fri, 22 Mar 2013 13:20:12 +0100
Message-ID: <CA+=hbbcbGnDWe7xhb9b0stMgOFnctV6kVpeqTGhRHP9xL1yhkg@mail.gmail.com>
To: Paolo Missier <Paolo.Missier@ncl.ac.uk>, James Cheney <jcheney@inf.ed.ac.uk>
Cc: public-prov-wg@w3.org
Hello James, Paolo,

do you have any suggestions for a better notation of these constructs, or
are you happy with the ones we have now?
The main issue is that the current notation deviates from what is used in
PROV-Constraints, and I'm not sure that we want that.
I'd like to resolve this issue before the telecon of 28th of March, so we
can release the document for internal review.

Paul suggested during the telecon to use double equal signs '==' instead of
a single '=', but I am not sure this solves the issue.

Another proposal is to include an explanatory paragraph, stating the

> In the constraints below, statements are made concerning the equality of
> sets of key-value pairs and sets of keys. For the sake of clarity, we will
> explain the used notations here.
> 1. To state that a set of  keys K1  and another set of keys K2 hold
> exactly the same keys, we use the notation K1 = K2.
> 2. To state that a set of key-value pairs KV1 and another set of key-value
> pairs KV2 hold exactly the same keys, with each key in KV1 mapped to
> exactly the same value as the same key in KV2, we use the notation KV1 =
> KV2.
> For example. the sets of keys {"k1", "k2"} and {"k1", "k3", "k4"} are not
> considered equal, since one of the sets holds keys the other does not.
> Analogously, the set of key-value pairs {("k1", e1),("k2", e2)} and the set
> {("k1", e2),("k2", e3)} are not considered equal, since the keys in the
> latter set map to different values than the same keys in the former set.

If you could share your view on this, that'd be great.
Thanks in advance!


@Paolo: in response to your example below, i'd say that in the case of

derivedByInsertionFrom(d2, d1, {(3,e1)} ),
derivedByInsertionFrom(d2, d1, {(4,e2)})

KV1=KV2 does not hold (since nor the keys, nor the values are equal),
and thus, this is not valid.

2013/3/7 Paolo Missier <Paolo.Missier@ncl.ac.uk>

>  Hi,
> I went back to James' review and I am not sure what an inference that
> derives KV1 = KV2 means, when KV1 and KV2 are ground. For example, what do
> we make of
> derivedByInsertionFrom(d2, d1, {(3,e1)} ),
> derivedByInsertionFrom(d2, d1, {(4,e2)})
> ?
> I think I need to understand this better
> --Paolo
> On 07/03/2013 10:45, Provenance Working Group Issue Tracker wrote:
> PROV-ISSUE-638 (TomDN): Notation of set of key-value pairs in contraints of PROV Dictionary [PROV-DICTIONARY]
> http://www.w3.org/2011/prov/track/issues/638
> Raised by: Tom De Nies
> Came up in the review by James, but was agreed to be handled after the first WD release.
> We need to get consensus of the group whether the notation KV1=KV2 is acceptable for constraints D9, D10, D11, D12.4, and D12.5, and whether considering equalities on sets of keys/KV pairs is a potential complication.https://dvcs.w3.org/hg/prov/raw-file/default/dictionary/releases/WD-prov-dictionary-20130312/Overview.html#impossible-removal-insertion-constraint
> --
> -----------  ~oo~  --------------
> Paolo Missier - Paolo.Missier@newcastle.ac.uk, pmissier@acm.org
> School of Computing Science, Newcastle University,  UKhttp://www.cs.ncl.ac.uk/people/Paolo.Missier
> PGP Public key: 0x45596549  - key servers: pool.sks-keyservers.net
Received on Friday, 22 March 2013 12:20:41 UTC

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