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Re: Linkbases, Topic Maps, and RDF Knowledge Bases -- help me
- From: "Thomas B. Passin" <firstname.lastname@example.org>
- To: xml-dev <email@example.com>
- Date: Fri, 06 Apr 2001 21:30:18 -0400
Uchi wrote (but why single him out in this thread?) -
> *My own opinion* is that RDF, XLink and Topic maps are all complementary,
> but that XTM tends to overlap with all of them, and might just be otiose
> (or might be the perfect intersection of the three, depending on your
I don't really see this so-called lower-level for RDF, higher level for
Topic Maps. They may be ***used*** that way by convention, but that's a
different matter. I see Xlink more as infrastructure that's useful for
either (potentially, at least), just as Hytime is infrastucture that can
support ISO-flavor topic maps.
Look at the kinds of things you probably want to do wth these systems:
- Assign properties
RDF: made for it, duck soup.
TM: Just as simple with ISO TMs using facets. For some reason I have
never understood, facets were removed in XTM, so now you have to assign
properties using appropriate relationships. Quite doable, but more clumsy.
- Make assertions about objects (or resources or ...)
RDF: Very feasible, although you may have to do some reification.
TM: easy with built-in associations.
- Create associations
RDF: very doable, but there is no native construct for assocations per
TM: made for it, duck soup.
- Create or use type hierarchies.
RDF: built-in machinery.
TM: almost built-in machinery. You have to roll your own, but the
constructs are there.
- Create or use class hierarchies
RDF: similar to hierarchies in constructs.
TM: Same as for hierarchies.
- Declare that one thing is an instance of type.
RDF: Very feasible
TM: built-in, duck soup
RDF: feasible but must be layered on top of RDF (as it is now).
TM: feasible but must be layered on top, primarily no doubt by defining
the nature of various association topics. May become built-in in the
- Constructs for various container structures.
TM: weaker, only has the equivalent of bags.
RDF: no particular built-in machinery.
TM: built-in, elaborate machinery (scopes)
- Merge maps or documents.
RDF: conceivable but no particular provisions.
TM: strong built-in machinery (once the XML folks get through arguing
about the ins and outs of it).
- Easy to read fragments. Of course this is a matter of taste to some
degree. For me, TMs are easier to read than RDF.
So both RDF and TM have strengths and weaknesses. But I really don't see
the high-level vs low-level thing at all.
Good Grief, I come home from work and what do I find? 500 messages about
Topic maps and RDF! Amazing.