Re: Bitzi File Metadata RDF Dump

* Peter Crowther
| 
| And that, I think, is the key point.  I feel that it is a mistake to
| confound URIs (especially URLs) and concepts, and that the Topic Map
| separation of Topics and Occurrences might work better.  Or it might
| not.

Actually, topic maps have a number of features that allow you to
control possible confusion in this area. The most obviously relevant
is the distinction between subject address and subject indicator.

A topic can be assigned a URI as a subject address, which means that
the topic is reifying the addressed resource (the subject of the topic
_is_ the resource). A topic can also be assigned any number of URIs as
subject indicators, which means that the topic reifies whatever is
discussed or identified by the addressed resources (the subject of the
topic is indicated by the resource). This provides (at least in
theory) a clean separation between URIs that identify resources and
URIs that identify concepts.

Occurrences are intended to be used for indicating that a resource
contains information relevant to a topic, and does not imply any kind
of relationship between the topic and the resource beyond that. I am
not sure how you would use this to avoid confusing URIs with concepts.

| TMs are designed to be self-contained; RDF is designed to sprawl.

There is no difference between TMs and RDF here. TMs are designed to
be automatically mergeable, and they are. They are usually being used
as self-containing entities, admittedly, but the technology is still
new, and that is just the easiest way to use them.

| You need some globally-visible namespace if the sprawl is to be
| interpreted.

Topic maps actually have another feature that may be helpful in this
regard: topic namespaces. Topics have names, and the standard requires
that names be unique within each topic namespace, where a topic
namespace is a set of topics that describe the context in which the
name is valid. (Scoping is used to define topic namespaces.)

This allows you to name one topic Paris (in the context of France),
and another Paris (in the context of Greek mythology) without fear
that they will be confused with one another.

So in theory you could use scoped names as your globally-visible
namespace. 

--Lars M.

Received on Sunday, 7 October 2001 17:45:30 UTC