My interpretation (which does not imply endorsement) is that the majority of bf predicates are currently limited by domain and range of either Work or Instance, and the intent is that Work / Instance / HeldItem are intended (but not formally specified) to be disjoint.    There have been many discussions on the list and elsewhere about whether a predicate is to be used on a Work or Instance, and how hard it is to generate that from MARC records. The resolution of that complexity is non-trivial and inevitably there will have to be trade-offs between purity and practicality.

R

On Mon, Nov 10, 2014 at 12:57 PM, Karen Coyle <[log in to unmask]> wrote:
On 11/10/14 10:48 AM, Robert Sanderson wrote:


However I'll object to the two level characterization on the following grounds:

1.  It's at least three level with Work, Instance and HeldItem.

2.  It's really the four level FRBR model, given the bf:expressionOf predicate, just that *cough* you have to infer that the subject of that predicate is an Expression-y type of Work, rather than a Work-y type of Work.

Yes, I would prefer to have bf:Expression as a class and be done with it, or to get rid of the FRBR work around predicates (expressionOf and hasExpression)

 Rob, in your interpretation (because I'm not sure that this is baked into the BF vocabulary) is every predicate limited in its use to only one of the 'levels'? Or is there some fluidity between the classes of bf:Work, bf:Expression and the annotation bf:HeldItem?

kc








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Rob Sanderson
Technology Collaboration Facilitator
Digital Library Systems and Services
Stanford, CA 94305

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Karen Coyle
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m: +1-510-435-8234
skype: kcoylenet/+1-510-984-3600



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Rob Sanderson
Technology Collaboration Facilitator
Digital Library Systems and Services
Stanford, CA 94305