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Dear Karen,

I try to take you questions in turn...


"1)if you have, for example, a simple geographic property, how do you 
know if it is a simple subject heading or something that can only be 
used in a complex subject? A less ambiguous example might be a 
temporalElement, something like "1940-1945." This probably cannot be 
used as a subject heading by itself. Is there a rule in the OWL data 
that indicates this? (I believe that I am referring to the 
free-floating subdivisions that cannot be used alone, but there may be 
other such subdivision types in LCSH as well.)"

Let's use this example:

Baltic States--History--1940-1991

You're right, no independent record exists for the Temporal component of this pre-coordinated heading.  In the MADS/RDF model "1940-1991" still becomes a Temporal Authority but it's basically baked into the data.  It is accessible as a blank node and not referenceable as a first-class resource.  Take the following, truncated RDF/XML snippet:

<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#">
<Authority rdf:about="http://id.loc.gov/authorities/sh92006091" xmlns="http://id.loc.gov/ontologies/mads/2010/11#">
 	<rdf:type rdf:resource="http://id.loc.gov/ontologies/mads/2010/11#ComplexSubject"/>
 	<authoritativeLabel>Baltic States--History--1940-1991</authoritativeLabel>
 	<componentList rdf:parseType="Collection">
 	 	<Geographic rdf:about="http://id.loc.gov/authorities/sh85011369"/>
 	 	<Topic rdf:about="http://id.loc.gov/authorities/sh85061212"/>
 	 	<Temporal rdf:nodeID="a1940-1991">
 	 	 	<rdf:type rdf:resource="http://id.loc.gov/ontologies/mads/2010/11#Authority"/>
 	 	 	<authoritativeLabel>1940-1991</authoritativeLabel>
 	 	 	<elementList rdf:parseType="Collection">
 	 	 	 	<TemporalElement>
 	 	 	 	 	<elementValue>1940-1991</elementValue>
 	 	 	 	</TemporalElement>
 	 	 	</elementList>
 	 	</Temporal>
 	</componentList>
</Authority>
</rdf:RDF>

Note that two of the components ("Baltic States" and "History") that make up this particular pre-coordinated heading are identified with HTTP URIs found in the componentList.  You can follow those URIs to ID and see that standalone records exist for "Baltic States" and "History."  But, you'll note that the component for "1940-1991" is basically fully expressed in the above snippet because no record exists for this particular heading.  If this were loaded into a system, "1940-1991" would essentially become a *local* Temporal Authority.  


"2)Isn't it the case that a variant heading could be composed of a 
variant simple type in position 1 followed by authoritative simple 
types in the subsequent positions? (and perhaps even an authoritative 
entry in position one and a variant entry in a subsequent position?)"

Yes.  In fact, this will often be the case with NameTitle records, where the Name exists as a distinct Authority but there are many variations of a title.


"3)What does the "and/or" indicate in the above section? What does it 
mean to have two or more authoritative AND two or more variant records 
in a complex record?"

It means that a ComplexType could be composed of two or more Variant records or two or more Authority records or some combination of Variant and Authority records.


Best,

Kevin

________________________________________
From: Metadata Object Description Schema List [[log in to unmask]] On Behalf Of Karen Coyle [[log in to unmask]]
Sent: Monday, December 06, 2010 08:53
To: [log in to unmask]
Subject: Re: [MODS] madsrdf: Question about subject

Quoting Simon Spero <[log in to unmask]>:

)
>
> The MADS/RDF Vocabulary Description
> <http://www.loc.gov/standards/mads/rdf/>states  (2.3) that
> "ComplexType describes [...] types by aggregating two or
> more Authority and/or two or more Variant records each of a
> SimpleType". Thus, it is not possible for a ComplexType to have a component
> list with only one member.

Simon thanks for finding the relevant section. Now I have a couple of
other questions:

1) if you have, for example, a simple geographic property, how do you
know if it is a simple subject heading or something that can only be
used in a complex subject? A less ambiguous example might be a
temporalElement, something like "1940-1945." This probably cannot be
used as a subject heading by itself. Is there a rule in the OWL data
that indicates this? (I believe that I am referring to the
free-floating subdivisions that cannot be used alone, but there may be
other such subdivision types in LCSH as well.)

2) Isn't it the case that a variant heading could be composed of a
variant simple type in position 1 followed by authoritative simple
types in the subsequent positions? (and perhaps even an authoritative
entry in position one and a variant entry in a subsequent position?)

3) What does the "and/or" indicate in the above section? What does it
mean to have two or more authoritative AND two or more variant records
in a complex record?

I suspect that there is something buried deep in the OWL definitions
that may clear this up, but like my first question, I haven't found it.

kc


>
> However, this same quotation is a good example of some of the fundamental
> confusions that render the ontology as a whole inconsistent.
>
>    - A restriction is given in the text but not stated in the ontology (that
>    component list must be a List with at least two members, and that each
>    member must be a SimpleType and either an Authority or a Variant)l. This
>     restriction can be expressed in OWL.
>    - Authority and Variant  are disjoint (one is a subclass of skos:Concept;
>    the other a subclass of skosxl:Label). It is not clear what
> intuitive class
>    corresponds to "Concept or Label".
>    - The examples that use a componentList contain members that are
>    SimpleTypes but which are not marked as  either being instances
> Authority or
>    of Variant.
>    - It is not intuitively clear what is denoted by the aggregation of a
>    Label with a Concept.
>    - The style of specification makes it difficult to express rules for the
>    order of subdivisions that are part of the SCM, making it less useful to
>    organizations following LC cataloging and policy standards (for
> example, LC)
>
> The specification fails to capture any of the semantics of coordinated
> headings. There are some semantics that differ  depending on whether one is
> applying a faceted or subdivision interpretation to these coordinate
> headings, but much of the semantics is common to both, and none are
> captured.
>
> Simon
> p.s.
> I would avoid using the word
> *property<http://philpapers.org/browse/property-nominalism>
> * here, as it has pre-existing Ontological meaning. 2.2 of MADS/RDF shows
> an  eliminativist approach to Properties that would be significant were it
> not clear from the text that it it is un-intentional as well as
> un-intensional.
>



--
Karen Coyle
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ph: 1-510-540-7596
m: 1-510-435-8234
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