Re: Tim Berners-Lee on the Semantic Web

From: Karen Coyle <lists_at_nyob>
Date: Tue, 3 Nov 2009 10:24:19 -0800
To: NGC4LIB_at_LISTSERV.ND.EDU
Quoting Ross Singer <rossfsinger_at_GMAIL.COM>:


> My questions would be -- if order matters (and... I think it does,
> yeah?), these should probably be in an rdfs:Seq or have some notion of
> the order of coordination.
>

Order is complicated in LCSH (as is everything else ;-)). In a given  
heading, the order that the subfields are written in the MARC record  
is the order that must be retained. In some cases, changing the order  
actually changes the meaning of the heading. HOWEVER, the order does  
not give you the facet type. So in some faceted systems, you have a  
fixed number of facets and they are always in the same order:

topic / place / time / genre  (or something like that)

LCSH can have any combination of these (that's an oversimplification,  
but good enough), and all except the first facet are optional. For  
that reason, one must retain the facet type (in MARC that means $x vs.  
$v or $z, etc.) in order to reconstruct the semantics of the  
individual facets.

In subject headings with names you have a name portion and a facet  
portion. The facet portion uses subfields vxyz. All of the rest is the  
name portion:

$aInternational Congress of Writers for the Defense of Culture$n(1st  
:$d1935 :$cParis, France)$vFiction.
=
name: $aInternational Congress of Writers for the Defense of  
Culture$n(1st :$d1935 :$cParis, France)
facet: $vFiction

kc

-- 
Karen Coyle
kcoyle@kcoyle.net http://kcoyle.net
ph: 1-510-540-7596
m: 1-510-435-8234
skype: kcoylenet
Received on Tue Nov 03 2009 - 13:26:16 EST