W3C home > Mailing lists > Public > public-prov-wg@w3.org > September 2011

Re: PROV-ISSUE-64 (definition-use): definition of use [Conceptual Model]

From: Luc Moreau <L.Moreau@ecs.soton.ac.uk>
Date: Fri, 09 Sep 2011 15:21:37 +0100
Message-ID: <EMEW3|03f867cf497803ac46a7a3c9f7da1278n88FLg08L.Moreau|ecs.soton.ac.uk|4E6A20F1.50400@ecs.soton.ac.uk>
To: public-prov-wg@w3.org
Hi Simon,

On 09/09/2011 02:59 PM, Simon Miles wrote:
> Hi Luc,
>
>    
>> I may not have been clear. I think that the requirement of roles to
>> define derivation is a stronger justification than data structure
>> uniformity.
>>      
> OK. I think this raises three sub-issues: (i) that is not the
> justification for mandatory roles currently given in the text; (ii)
>    
Yes, text would need to be change

> the use of roles in derivation assertions sounds like role types
> rather than role names, i.e. there appears to be no necessity for the
>    
no, in derivation, it's definitely role names you need, and unicity is 
required.
> roles mentioned to be unique; (iii) roles are optional in derivation
> assertions, so it seems odd that this be a rationale for them being
> mandatory in other assertions.
>    
optional to assert, but they do exist, as per inference.
exactly like in use, roles are optional to assert
>    
>> You still seem not to take into account the optional nature of asserting
>> roles. Maybe, it's a question of presentation in the document.  But
>> ultimately, we are
>> telling people you are free not to express roles. Under the bonnet, there
>> will be an unspecified role. I don't understand what the problem is with
>> this approach, where a default value is provided.
>>      
> My problem with this approach is that I am unclear what "under the
> bonnet" really means. I also agree with Graham's point that, whatever
> it is, I don't know whether we should be standardising it.
>
>    
forget this sentence, sorry.
I meant to say that not asserting a role is defined as asserting a role
in the set "unspecified".
> Regardless of any of the above, I still think the opaqueness of "Roles
> are mandatory since they allow for uniform data structures" is the
> most pressing issue. I think it answers a necessary question (why
> mandatory?) but in an unhelpful way.
>    
We would drop this statement, since derivation is a better justification.

Luc
> Thanks,
> Simon
>
>
> On 5 September 2011 10:20, Graham Klyne<GK@ninebynine.org>  wrote:
>    
>> On 05/09/2011 08:17, Luc Moreau wrote:
>>      
>>> You still seem not to take into account the optional nature of asserting
>>> roles. Maybe, it's a question of presentation in the document. But ultimately,
>>> we are
>>> telling people you are free not to express roles. Under the bonnet, there
>>> will be an unspecified role. I don't understand what the problem is with
>>> this approach, where a default value is provided.
>>>        
>> I think there may be a mismatch here between designing a *system* and defining a
>> *standard* - the point of a standard is to specify what is visibly exchanged
>> between systems.
>>
>> In particular, if the role is optional, then it is unhelpful to say "Under the
>> bonnet, there will be an unspecified role", because what exists "under the
>> bonnet" is exactly an implementation choice.  If I write a system that uses
>> provenance information in a limited fashion that never involves roles (which is
>> OK, as you have said they are optional), then there is no unspecified role under
>> the bonnet.
>>
>> Thus, if the presence of a role is optional in the exchange of provenance
>> information, then I think it should be optional in the model, as it is the
>> exchangeable provenance information that we need to model here.  Maybe, as you
>> say, this is simply a matter of choosing appropriate phrasing.
>>
>> #g
>> --
>>
>>
>>      
>
>
>    

-- 
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 Friday, 9 September 2011 14:22:23 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Thursday, 26 April 2012 13:06:41 GMT