W3C home > Mailing lists > Public > public-lld@w3.org > October 2011

Re: Disjointedness of FRBR classes

From: Ross Singer <ross.singer@talis.com>
Date: Wed, 26 Oct 2011 21:30:28 +0100
Message-ID: <CAPJqReP5npFsav+qsARMoq_3RAfyKhyH7KcCQZM+T_vYcoUvGQ@mail.gmail.com>
To: Tom Baker <tbaker@tbaker.de>
Cc: Karen Coyle <kcoyle@kcoyle.net>, public-lld@w3.org
On Wed, Oct 26, 2011 at 9:10 PM, Tom Baker <tbaker@tbaker.de> wrote:

> Would it help simply to stop saying that the WEMI classes are disjoint?

What's the benefit in this?  What have I said if I say that this thing
is a Work and an Expression (since neither of these exist in nature)?

If I am talking about a Book, I'm talking about a Book, not an
Expression or Manifestation (although those concepts may be abstractly
part of what is a Book).

If anything, removing the restrictions seems to dilute the point of
bothering with FRBR at all.

-Ross.

> Stating that Resource X is a Work and then stating that Resource X is an
> Expression would be semantically acceptable.  A Work description could
> potentially be seen as a Work "view" of Resource X while an Expression
> description could -- without formal contradiction -- been seen as an Expression
> "view" of the same Resource X.  What would break?  W, E, M, and I descriptions
> could still be exposed as separate graphs, so the distributed management of
> resource description -- drawing on bits from here and there -- would still be
> supported.  In other words, one would not need to sacrifice the practical
> benefits of FRBR.
>
> For this to work would of course require consistent data, but this could be
> achieved by using the strong OWL ontology or the Application Profile, as
> needed, when the data is created.
>
> The _formal-semantic_ barriers to merging WEMI data with legacy data (with WEMI
> entities smushed into a single undifferentiated block) -- or with data that
> simply slices up the world differently -- would simply melt away.  It would
> come down to the classic, and unavoidable, judgement calls about how to
> interpret data from a diversity of sources and perspectives.
>
> Tom
>
>> Meanwhile, I think that Tom is right in that this "instance" of FRBR
>> is designed for a situation with trained catalogers, as well as
>> applications that enforce the constraints. It defines a closed
>> world. (I'm less sure that the Tillett/Murray definition is more
>> open, but I would like it to be.) The AP model might be able to
>> create a more open world for it be part of.
>>
>> kc
>>
>> Quoting Tom Baker <tbaker@tbaker.de>:
>>
>> >On Wed, Oct 26, 2011 at 04:03:20PM +0100, Gordon Dunsire wrote:
>> >>> property "is realizer (corporate body) of" is disjoint with properties:
>> >>> - has name of the corporate body
>> >>> - has number associated with the corporate body
>> >>> - has place associated with the corporate body
>> >>> - has date associated with the corporate body
>> >>> - has other designation associated with the corporate body
>> >
>> >Okay, so we have [1]:
>> >
>> >    <frbrer:P2012> <rdfs:label> "is realizer (corporate body) of"@en .
>> >    <frbrer:P2012> <rdfs:range> <frbrer:C1002> .
>> >    <frbrer:P2012> <rdf:type> <owl:ObjectProperty> .
>> >    <frbrer:P2012> <rdf:type> <owl:NamedIndividual> .
>> >    <frbrer:C1002> <rdfs:label> "Expression"@en .
>> >    <frbrer:C1002> <rdf:type> <owl:Class> .
>> >    <frbrer:C1002> <rdf:type> <owl:NamedIndividual> .
>> >    <frbrer:P2012> <rdfs:domain> <frbrer:C1006> .
>> >    <frbrer:C1006> <rdfs:label> "Corporate Body"@en .
>> >    <frbrer:C1006> <rdf:type> <owl:Class> .
>> >    <frbrer:C1006> <rdf:type> <owl:NamedIndividual> .
>> >    <frbrer:P2012> <owl:propertyDisjointWith> <frbrer:P3045> .
>> >    <frbrer:P3045> <rdfs:label> "has place associated with the
>> >corporate body"@en .
>> >    <frbrer:P3045> <rdfs:domain> <frbrer:C1006> .
>> >    <frbrer:P3045> <rdf:type> <owl:NamedIndividual> .
>> >
>> >and then:
>> >
>> >    <frbrer:P2012> <owl:propertyDisjointWith> <frbrer:P3045> .
>> >
>> >I'm struggling to see the interoperability gains of putting all
>> >these "disjoint
>> >property" statements into the definitions of the base vocabulary.  Triples
>> >about disjointness are 45% of the 3930 triples in [1].
>> >
>> >>Property disjointness is given where the value of the object of an instance
>> >>triple should not be interpreted as referencing the same thing as for an
>> >>instance triple using a different property but with the same subject.
>> >
>> >As OWL2 puts it: "two properties are disjoint if there are no two individuals
>> >that are interlinked by both properties" [2].  I can understand why one would
>> >want to apply such precise semantics in controlled environments (e.g., a
>> >cataloging department) for the purposes of controlling the quality of data
>> >produced, but I do not see the benefit of imposing such strong
>> >semantics on the
>> >rest of the world by including them in the very definitions of properties and
>> >classes.
>> >
>> >To my way of thinking, the presence of these strong semantics
>> >seems to tell the
>> >world that nobody should even _think_ of using these vocabularies unless they
>> >really really know, understand, and subscribe to the precise interpretation
>> >encoded therein and are confident they can apply it correctly (and that
>> >speakers of Chinese, Spanish, and Arabic should hope the translations are
>> >good).  The semantically strong definition seems to imply that these
>> >vocabularies are really only intended for use by trained, professional,
>> >English-speaking library catalogers using OWL reasoners, and that
>> >nobody should
>> >even think of building on FRBR with additional properties without
>> >defining them
>> >with the same high degree of precision.
>> >
>> >If so, that feels like a missed opportunity, because FRBR is potentially very
>> >useful outside of that relatively small world.  Defining FRBRer without all
>> >this disjointness, on the other hand, would not at all preclude
>> >the application
>> >of strong interpretations when really needed in specific contexts, such as
>> >controlling the output of cataloging departments.
>> >
>> >In the end, though, I wonder if this strong disjointness is really
>> >supported by
>> >the FRBR model itself [3]?   For example, I read:
>> >
>> >    "On a pragmatic level, defining work as an entity in the model serves a
>> >    number of purposes. It enables us to give a name and draw
>> >relationships to
>> >    the abstract intellectual or artistic creation that encompasses all the
>> >    individual expressions of that work. ....  It is the entity defined as
>> >    work, therefore, that provides us with this grouping capability. ... On a
>> >    practical level, the degree to which bibliographic distinctions are made
>> >    between variant expressions of a work will depend to some extent on the
>> >    nature of the work itself, and on the anticipated needs of users and on
>> >    what the cataloguer can reasonably be expected to recognize from the
>> >    manifestation being described."
>> >
>> >In such places, the language of FRBR seems to suggest less a rigid
>> >ontology of
>> >the world "as it is" and more a set of distinctions that have value because
>> >they are useful in a pragmatic sense, e.g., in splitting parts of
>> >a description
>> >into separate bundles that can be maintained and referenced in a more
>> >distributed manner.  As Barbara Tillett and Ron Murray put it [4]:
>> >
>> >    E-R and OO modeling may be used effectively to create information systems
>> >    based on an inventory of "things of interest" and the relationships that
>> >    exist among them. Unfortunately, the things of interest in Cultural
>> >    Heritage institutions keep changing and may require redefinition,
>> >    aggregation, disaggregation, and re-aggregation. E-R and OO modeling as
>> >    usually practiced are not designed to manage the degree and
>> >kind of changes
>> >    that take place under those circumstances.
>> >
>> >Their reference to WEMI entities as "sub-graphs" which "reproduce
>> >bibliographic
>> >characteristics found useful by catalogers, scholars, other educationally
>> >oriented end-users, and to varying extents the public in general" -- as
>> >"views", or as "groups of statements that occupy different levels of
>> >abstraction" -- suggests a more flexible (and useful) basis for a formal
>> >expression of FRBR defined, perhaps, more along the lines of minimal semantic
>> >commitment.
>> >
>> >Tom
>> >
>> >[1] http://triplr.org/ntriples/iflastandards.info/ns/fr/frbr/frbrer/frbrer.rdf
>> >[2] http://www.w3.org/TR/2009/REC-owl2-primer-20091027/#a_DisjointObjectProperties
>> >[3] http://www.ifla.org/publications/functional-requirements-for-bibliographic-records
>> >[4] http://www.ala.org/ala/mgrps/divs/lita/publications/ital/prepub/index.cfm
>> >
>> >--
>> >Tom Baker <tom@tombaker.org>
>> >
>>
>>
>>
>> --
>> Karen Coyle
>> kcoyle@kcoyle.net http://kcoyle.net
>> ph: 1-510-540-7596
>> m: 1-510-435-8234
>> skype: kcoylenet
>
> --
> Tom Baker <tom@tombaker.org>
>
>
Received on Wednesday, 26 October 2011 20:30:57 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Wednesday, 26 October 2011 20:30:58 GMT