On May 22, 2013, at 5:22 AM, Owen Stephens <[log in to unmask]> wrote:

> On 22 May 2013, at 09:58, Stuart Yeates <[log in to unmask]> wrote:
>> As I understand it, the main question posed by is "Do we need a "lightweight abstraction layer""?
>> Equivalently, as I understand it, the question is "Can we attach the authority-related attributes directly to a person / document / place or do we need some separate resource for them?"
>> My answer is (a) yes we do need a separate resource for them and (b) we can do that very easily.
>> (a) yes we do need a separate resource for them
>> For Instances where the carrier is digital and we have a URL the instance, we already need to make a differentiation between our rdfs:Resource for metadata about the instance and the rdfs:Resource that is the instance. Otherwise we canít differentiate, for example, between the HTML version of the FRBR report and itís HTML catalog entry. Once we've made the distinction for digital Instances, having a different genre of 'thing' for our other entities in our model is a recipe for confusion.
> +1 (not sure my primary reasoning is the same, but agree with the point here and the conclusion)

It sounds like we're in agreement (but for different reasons). Thats an indicator of a good design. 

>> (b) we can do that very easily
>> In the foaf vocabulary there is a foaf:Person, a foaf:Document and foaf:primaryTopic which are what they say on the tin and have, I believe, exactly the semantics weíre looking for. foaf:Agent and geo:Point are obvious contenders for Organisation and Place.  We can reuse them directly or via semantic sugar (a la madsrdf:hasCloseExternalAuthority). There are other namespaces, with coverage of these areas; pretty much any of them is better than rolling our own. foaf also has the benefit of already being used by VIAF (and I believe it works for them, I've certainly not seen any complaints). 
> +1

It sounds like again we're in agreement in principal of the pattern. The disagreement then lies in minting new terms or reusing then from some other domain. It's a fair criticism, I just want to separate the points that folks agree to from ones they don't.

> but feel this ship has already sailed - previous replies have been clear that BIBFRAME/LoC want to control the namespace. But I completely agree that this type of approach works (and the University of Cambridge example followed this).

Indeed. From our preliminary analysis of linked data library patterns, while different groups used different URIs for these classes, the patterns (in general) were quite similar. Our analysis and implementation experience in linked data patterns outside of the library community helped confirm this as well. 

> What I'm not clear on is whether there is the need for this lot of things to be grouped (presumably by being subclassed from?) as BIBFRAME 'Authorities'. I can't see why you'd want to do this at the moment - could the arguments be put forward for this in particular as opposed to the 'lightweight abstraction' in general (which I think is what the document does)

The 'grouping' mechanism serves two (at least?) purposes. One as a mechanism for explanation ('Authority' vs trying to enumerate each example). The other is to support extensibility in a consistent, actionable manner. Stuart has listed some of these Authorities (Person, Topic, Organisation, Place, etc.) If one broadens the scope of BIBFRAME even slightly to support our traditional needs we start to see more.  A 'nearby' example would be the management of technical and product documentation across an huge, international organizations. In this case, the needs include refinement to Organisation, inclusion of Departments, etc. Once one moves beyond even these 'nearby' examples, the applications and use cases get even more interesting. Rather than say BIBFRAME should be everything to everyone and define everything (which it can't be), adding these extensibility mechanisms allows BIBFRAME to be used in a range of larger contexts and support even more of a free flow of data across descriptive communities. 

Eric Miller
President, Zepheira "The Art of Data" tel:+1.617.395.0229