Re: PROV-ISSUE-239 (TLebo): is wasGeneratedBy(e) meaningful? [prov-dm]

On Feb 6, 2012, at 5:57 PM, Paolo Missier wrote:

> The activity should not be optional, surely?

But it is!


All of the components except entity are optional, so DM lets me say "wasGeneratedBy(e)"
wasGeneratedBy(id,e,a,t,attrs)
id: an optional identifier id identifying the generation record;
entity: an identifier e identifying an entity record that represents the entity that is created;
activity: an optional identifier a identifying an activity record that represents the activity that creates the entity;
time: an optional "generation time" t, the time at which the entity was created;
attributes: an optional set of attribute-value pairs attrs that describes the modalities of generation of this entity by this activity.

so the activity _must_ be there, and if it's not named then we _must_ name one?

If so, then how do we tell the difference between that kind of optional and the truly optional references?



-Tim




> 
> -Paolo
> 
> On 2/6/12 9:19 PM, Provenance Working Group Issue Tracker wrote:
>> PROV-ISSUE-239 (TLebo): is wasGeneratedBy(e) meaningful? [prov-dm]
>> 
>> http://www.w3.org/2011/prov/track/issues/239
>> 
>> Raised by: Timothy Lebo
>> On product: prov-dm
>> 
>> Everything but entity is OPTIONAL in wasGeneratedBy.
>> 
>> If I say only wasGeneratedBy(e), what did I say? And why was I allowed to say it?
>> 
>> from WD3:
>> 
>> 
>> A generation record, written wasGeneratedBy(id,e,a,t,attrs) in PROV-ASN, has the following components:
>> 
>>     id: an optional identifier id identifying the generation record;
>>     entity: an identifier e identifying an entity record that represents the entity that is created;
>>     activity: an optional identifier a identifying an activity record that represents the activity that creates the entity;
>> 
>> 
>> 
> 
> 
> -- 
> -----------  ~oo~  --------------
> Paolo Missier - Paolo.Missier@newcastle.ac.uk, pmissier@acm.org
> School of Computing Science, Newcastle University,  UK
> http://www.cs.ncl.ac.uk/people/Paolo.Missier
> 
> 
>