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Re: How to state simple facts in RDF

From: Lars Marius Garshol <larsga@ontopia.net>
Date: Wed, 29 Jun 2005 17:48:57 +0200
To: public-swbp-wg@w3.org
Message-ID: <m3irzx2mfq.fsf@pavarotti.intern.opera.no>

* Christopher Welty
| I don't know anything about topic maps, but it sounds like from your
| syntactic example:
| [a] is-bankrupt(barings-bank : company)
| that you have some notion of "strong typing" (aka "sorts" in logic),
| that is, there are unary predicates that are somehow more essential
| than others. 

I don't know enough about logic to answer this, but we certainly know
unambiguously which predicate instances are unary and which ones are

| There has been a lot of work on this in the research community, and
| we are trying (through this forum) to educate the SW community about
| it, not surprising that many don't know about it, or even believe it
| doesn't exist.

| you can create special relations to differentiate the "essential"
| from "nonessential" associations to classes:
| [b] essentialType rdfs:subproperty rdf:type
|     nonessentialType rdfs:subproperty rdf:type
|     barings-bank essentialType company
|     barings-bank nonessentialType bankrupt

That's certainly an alternative. I think probably creating a different
property for normal typing is going to be unacceptable, but using a
subtype for the "nonessential type" might work.
| [c] EssentialClass rdf:type rdf:Class
|     NonessentialClass rdf:type rdf:Class
|     Company rdf:type EssentialClass
|     bankrupt rdf:type NonessentialClass
|     barings-bank rdf:type company
|     barings-bank rdf:type bankrupt

Yes, this is theoretically also possible, but there are esthetic
issues with it. :)
| Of course most non-essential classes can just be turned into
| relations:
| [d] barings-bank rdf:type Company
|     barings-bank financialStatus bankrupt

In modelling that is possible, but an automated translator would not
be able to do this, I think.
| Assuming you are interested in automatically translating the syntax
| of [a] into rdf, [...]

We are.

| [...] I think [b] would be easiest to generate automatically from
| syntax, [c] is not much harder (it may require two passes) and would
| be my preference, as I believe it is closer to what you really mean.
| [d] would probably be hard to do automatically.

I agree completely.
| I'm expecting that, in order to do translation between any two
| languages, some special vocabulary will be needed in each to ensure
| as much of the semantics of the "source" language is preserved.  So
| both [b] and [c] would require some special vocabulary to support
| translation.

Yes, and as you say, requiring additional vocabulary is acceptable.

Lars Marius Garshol, Ontopian         <URL: http://www.ontopia.net >
GSM: +47 98 21 55 50                  <URL: http://www.garshol.priv.no >
Received on Wednesday, 29 June 2005 15:49:12 UTC

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