FRBR was developed for the specific purpose of modeling library catalog data. I give the backstory on FRBR in chapter 5 of my book, "FRBR Before and After." The most innovative aspect of FRBR was the development of a multi-entity view of creative works. Referred to as "group 1" of three groups of entities, the entities described there are Work, Expression, Manifestation, and Item (WEMI). They are aligned with specific bibliographic elements used in library catalogs, and are defined with a rigid structure: the entities are linked to each other in a single chain; the data elements are defined each as being valid for one and only one entity; all WEMI entities are disjoint.
In spite of these specifics, something in that group 1 has struck a chord for metadata designers who do not adhere to the library catalog model as described in FRBR. In fact, some mentions or uses of WEMI are not even bibliographic in nature.* This leads me to conclude that a version of WEMI that is not tied to library catalog concepts could provide an interesting core of classes for metadata that describes creative or created resources.
We already have some efforts that have stepped away from the specifics of FRBR. From 2005 there is the first RDF FRBR ontology, frbrCore, which defines the entities of FRBR and key relationships between them as RDF classes. This ontology breaks away from FRBR in that it creates super-classes that are not defined in FRBR, but it retains the disjointness between the primary entities. We also have FRBRoo which is a FRBR-ized version of the CIDOC museum metadata model. This extends the number of classes to include some that represent processes that are not in the static model of the library catalog. In addition we have FaBiO, a bibliographic ontology that uses frbrCore classes but extends the WEMI-based classes with dozens of sub-classes that represent types of works and expressions.
I conclude that there is something in the ability to describe the abstraction of work apart from the concrete item that is useful in many areas. The intermediate entities, defined in FRBR as expression and manifestation, may have a role depending on the material and the application for which the metadata is being developed. Other intermediate entities may be useful at times. But as a way to get started, we can define four entities (which are "classes" in RDF) that parallel the four group 1 entities in FRBR. I would like to give these new names to distance them from FRBR, but that may not be possible as people have already absorbed the FRBR terminology.
FRBR / option1 / option2
work / idea / creative work
expression / creation / realization
manifestation / object / product
item / instance / individual
My preferred rules for these classes are:
- any entity can be iterative (e.g. a work of a work)
- any entity can have relationships/links to any other entity
- no entity has an inherent dependency on any other entity
- any entity can be used alone or in concert with other entities
- no entities are disjoint
- anyone can define additional entities or subclasses
- individual profiles using the model may recommend or limit attributes and relationships, but the model itself will not have restrictions
Given this freedom, how would people choose to describe creative works? For example, here's one possible way to describe a work of art:
creator: Paul Klee
genre: abstract art
size: 9 x 9
base material: paper
material: watercolor, pastel, ink
And here's a way to describe a museum store's inventory record for a print:
creator: Paul Klee
genre: abstract art
description: 12-color archival inkjet print
size: 24 x 36 inches
There is also no reason why a non-creative product couldn't use the manifestation class (which is one of the reasons that I would prefer to call it "product," which would resonate better for these potential users):
description: dining chair
dimensions: 26 x 23 x 21.5 inches
weight: 21 pounds
Here is the sum total of what this core WEMI would look like, still using the FRBR terminology:
<http://example.com/Work> rdf:type owl:Class ;
rdfs:label "Work"@en ;
rdfs:comment: "The creative work as abstraction."@en .
<http://example.com/Expression> rdf:type owl:Class ;
rdfs:label "Expression"@en ;
rdfs:comment: "The creative work as it is expressed in a potentially perceivable form."@en .
<http://example.com/Manifestation> rdf:type owl:Class ; rdfs:label "Manifestation"@en ;
rdfs:comment: "The physical product that contains the creative work."@en .
<http://example.com/Item> rdf:type owl:Class ;
rdfs:label "Item"@en ;
rdfs:comment: "An instance or individual copy of the creative work."@en .
I can see communities like Dublin Core and schema.org as potential locations for these proposed classes because they represent general metadata communities, not just the GLAM world of IFLA. (I haven't approached them.) I'm open to hearing other ideas for hosting this, as well as comments on the ideas here. For it? Against it? Is there a downside?
* Examples of some "odd" references to FRBR for use in metadata for: