Hi Karen – Yes there certainly is a terminology issue, particularly because the expression “RDF resource” does not have a formal definition, anywhere (that I have ever been able to find). However, whenever I encounter the expression it seems to be used in the sense that I’m using it.   Which is this:
In any RDF triple the object is a literal or an RDF resource.  A literal is of course a resource; and I am making a distinction between “resource” and “RDF resource”.
So, the object of a triple is either:

1.       a literal, in which case it’s enclosed in quotes (assuming turtle serialization); or

2.       not enclosed in quotes, in which case it is an RDF resource URI (either enclosed by curly braces or using namespace prefix notation), or a blank node id.

For case 2, the URI can be dereferenced resulting in an RDF description or if it is a blank node it points to an RDF description.

Do you agree (so far)?  If you think I’m using the expression “RDF resource” incorrectly then what is your definition?  If you think “RDF resource” and “resource” mean the same thing, I disagree, but then, I could be wrong, since “RDF resource” has no formal definition.  But I’m using it in the sense that I see it used.

Anyway, having said all that, getting back to the example at hand

      bf:electronicLocator  [
                 a    bf:ElectronicLocator ;
                  rdf:value   “” ] ;

I maintain that it would be incorrect to instead say:

bf:electronicLocator  <” >

because that would imply that you can retrieve RDF by dereferencing , which (as far as I know) you can’t.


From: Bibliographic Framework Transition Initiative Forum [mailto:[log in to unmask]] On Behalf Of Karen Coyle
Sent: Sunday, November 15, 2015 8:30 PM
To: [log in to unmask]
Subject: Re: [BIBFRAME] Properties of Item proposal

On 11/12/15 12:05 PM, Denenberg, Ray wrote:
Hi Joseph – thanks for the comments and questions.  I want to address two points, while we are still discussing the other suggestions.

bf:electronicLocator is, at present, conceived to be a datatype property; its expected value is a literal.  We could change that to an object property if that’s what people want, however, the URI would still be a literal, because it is not an RDF resource.   In the example, the electronic locator is and this is not an RDF resource. (By RDF resource, we mean, you can dereference the URI and get RDF in response. You can’t for this URI.)

Ray, can you say more about this concept of a non-resource? AFAIK, many URIs do not dereference to  "RDF in response", but they are still considered resources in RDF. I'm looking at:

"90. Resource
In an RDF context, a resource can be anything that an RDF graph describes. A resource can be addressed by a Unified Resource Identifier (URI)<>." [1]

"Any IRI<> or literal<> denotes something in the world (the "universe of discourse"). These things are called resources. Anything can be a resource, including physical things, documents, abstract concepts, numbers and strings; the term is synonymous with "entity" as it is used in the RDF Semantics specification [RDF11-MT<>]."[2]

There is similar language in the RDF 1.1 primer. [3]

This might be a terminology issue, but even accepting a different terminology, I'm not aware of any distinction where a response to the dereferencing of an IRI must be RDF (meaning? ntriples? JSON-LD?) rather than any RDF:resource (e.g. a jpeg file, an html file, an avi file).


If bf:electronicLocator were to be redefined as an object property, then instead of this:

          a                                        bf:Item ;
          bf:electronicLocator      “”  ;

It might look like this:

          a                                        bf:Item ;
          bf:electronicLocator  [
                                                   a    bf:ElectronicLocator ;
                                                    rdf:value   “” ] ;

Where here we now have defined class bf:ElectronicLocator, but the URI is still a literal.

Second, should bf:itemOf (property of item) have a reciprocal property, bf:hasItem (property of Instance).
I don’t know; opinions are welcomed on this question.  We did not include it in the draft for this reason: an item knows (or should know) what Instance it is an Item of.  An Instance in general does not know the existence of all items that claim to be an item of that Instance. So if there were to be a property bf:hasItem, it could be used within an Instance to point to all items that that Instance knows about with the disclaimer that it doesn’t claim to point to all its items. If, as such, this would be useful then we can add the property.  (The same dilemma applies to instanceOf and hasInstance. And granted, these are both included in BIBFRAME 1.0.)


From: Bibliographic Framework Transition Initiative Forum [mailto:[log in to unmask]] On Behalf Of Joseph Kiegel
Sent: Tuesday, November 10, 2015 1:39 PM
To: [log in to unmask]<mailto:[log in to unmask]>
Subject: [BIBFRAME] Properties of Item proposal

Items in BIBFRAME may serve different purposes, which is not addressed in the Items proposal.  A relatively narrow purpose is to support the user task obtain, while a more complex one is to support a working circulation system.  The properties elaborated in the proposal are not sufficient even for the user task obtain.  Here are comments on them.

bf:electronicLocator:  should the expected value be a URI?  It seems odd to express URLs as literals in linked data.

bf:heldBy and bf:subLocation:  the MARC holdings format and many library systems recognize three levels of location information: organization, library and sublocation within a library.  BIBFRAME should support the same number of levels:  for example, it should add a property such as bf:location, which is intermediate between bf:heldBy and bf:subLocation.

bf:heldBy University of Washington Libraries
bf:location:  Art Library
bf:subLocation:  Reference stacks

bf:heldBy University of Washington Libraries
bf:location:  Engineering Library
bf:subLocation:  Reference stacks

Without bf:location, reference or general stacks locations in different buildings appear to be the same.

bf:itemOf:   is a reciprocal property needed?  For example, bf:hasItem, a property of bf:Instance with an expected value of bf:Item.

Two properties are lacking from the proposal:  bf:itemStatus and bf:circulationCharacteristic

bf:itemStatus:  it is crucial to inform users of the status of an item, e.g. available, checked out, missing, withdrawn, at the bindery, etc.

bf:circulationCharacteristic:  another important aspect of materials is the general policy that governs them, e.g. circulating or library use only.  It is tempting to try to include this characteristic in bf:itemStatus, but they are independent aspects.  LUO materials may be missing, at the bindery or even checked out (e.g. faculty loans of reference materials).


Karen Coyle

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