On Thu, Oct 14, 2010 at 10:10:37PM +0200, Bob Ferris wrote:
> during a discussion about agent groups, I noticed that
> dcterms:AgentClass has a new super class, dcterms:AgentClass. I wasn't
> really aware of that change due to the recent revision from 2010-10-11,
> because it isn't really noticed in the changed log (and that's why, I
> was very suprised).
> Did I miss something? In the previous revision from 2010-01-14 the super
> class of dcterms:AgentClass is rdfs:Class (see [1]). However, in the
> recent revision[2] there is a change without any notice, e.g. a
> dcterms:modified statement.
...
> [1] http://dublincore.org/2008/01/14/dcterms.rdf#AgentClass
> [2] http://dublincore.org/2010/10/11/dcterms.rdf#AgentClass
Hi Bob,
Thank you for spotting this! No, this was not a deliberate
change. I am as surprised as you are, and I am surprised to
see that the discrepancy is reflected in the source data used
to generate both the Web documentation and and the schemas.
In order to find out when it changed in the source data
I'd have to look at the SVN change logs, but I would first
have to read up on how to view the history of changes for a
specific file.
According to the relevant Decision document of 2008-10-14,
the decision was indeed to declare dcterms:AgentClass to be
subClassOf rdfs:Class [1].
The term declaration now (2010-10-11) says:
dct:AgentClass rdf:type rdfs:Class
dct:AgentClass rdfs:subClassOf dct:AgentClass
which seems like a harmless bit of redundancy because "All
classes are subclasses of themselves" [2] -- a case of stating
something explicitly that can be inferred.
What is not clear to me, with a brief look at RDF Semantics,
is whether we are actually losing information by not saying
in 2010 what the term declaration said in 2008, i.e.:
dct:AgentClass rdf:type rdfs:Class
dct:AgentClass rdfs:subClassOf rdfs:Class
All classes are subclasses of rdfs:Resource, but are they
also all subclasses of rdfs:Class (i.e., can this second
triple simply be inferred)?
Either way, this is clearly an error of transcription somewhere
along the way and needs to be corrected. I can correct this
with an errata note. I'm wondering how urgent this is, as
I am currently very busy preparing for next week's DC-2010
conference.
Tom
[1] http://dublincore.org/documents/2008/01/14/domain-range/#AgentClass
[2] http://www.w3.org/TR/2004/REC-rdf-mt-20040210/#technote
--
Thomas Baker <[log in to unmask]>
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