Re: Linkbases, Topic Maps,and RDF Knowledge Bases -- help me understand, please

[John Cowan <jcowan@reutershealth.com>]

Michael Champion wrote:


> CONCEPTUALLY (not syntactically, politically, religiously, or
> organizationally), what are the similarities and and the differences among
> XTM topic maps, XLink link bases, and RDF knowledge bases (or whatever the
> correct term for a "web" of RDF is)?

Here's my take on it, which surely is not complete and may not be
100% correct.  By "resources" I mean the W3C sense: anything which
has an URI.

1) RDF expresses *binary relations* between *resources*, and also relations
between a resource and a literal string.

2) XLink expresses *multi-way* relations (with role labels) between
resources, and also specifies preferred traversal paths (arcs) between
the related resources.

3) XTM expresses multi-way relations (with role labels) between
*topics*, where topics represent subject matters, which may be either
themselves resources or non-addressable objects (like people) who can
be described by resources.

Each has its own idiosyncratic XML syntax.  Because RDF is the lowest
level of the three, it should be possible to express both XLink and
XTM in RDF syntax as well as native syntax.

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