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Re: DAML+RDFS: potentials for simplifications?

From: Thomas B. Passin <tpassin@home.com>
Date: Wed, 28 Nov 2001 20:43:24 -0500
Message-ID: <002801c17877$3c681520$7cac1218@cj64132b>
To: <www-rdf-logic@w3.org>

> If my interpretation (that DAML is based on a set of axioms, basically
> independent from RDF) is correct, lots of simplification could be
> introduced into DAML. In this e-mail I want to present a first thought,
> mainly for discussion purposes.
> The following example (from http://www.daml.org/2001/03/daml+oil-ex.daml)
> shows a DAML-Class definition using RDFS:
> <daml:Class rdf:ID="Animal">
>   <rdfs:label>Animal</rdfs:label>
>   <rdfs:comment>
>     This class of animals is illustrative of a number of ontological
> idioms.
>   </rdfs:comment>
> </daml:Class>
> <daml:Class rdf:ID="Male">
>   <rdfs:subClassOf rdf:resource="#Animal"/>
> </daml:Class>
> <daml:Class rdf:ID="Female">
>   <rdfs:subClassOf rdf:resource="#Animal"/>
>   <daml:disjointWith rdf:resource="#Male"/>
> </daml:Class>
> This looks rather complicated, and again, I can not see the reason for
> RDFS-based notation; if my conclusions from part I of this e-mail are
> correct (i.e. it is possible to drop  RDFS from the syntax of DAML), then
> one could write down the same information using the following simplified
> syntax:

From my point of view,  there are two essential differences between your
first (above) and second (below) example:

1) There is really no difference in the syntax between them except that the
second example does not use namespaces.  Therefore a processor needs some
other way to understand how you want to process them.  It can't be expected
to know without hints that your <Class/> is not the same as my

<Class subject='physics'>Physics 7.01
    <days>Mon,Wed</days><time>11:00 AM</time>

If you don't use namespaces, you need some other way to say what system you
are using.

2) You need a set of conventions so a processor would  know how to interpret
the various constructions.  It's not always obvious, as witness all the
discussion on this list even though there are fairly developed documents
defining the syntax, etc.  To create such a set of conventions would amount
to writing a new spec to replace RDF, or DAML and RDF.  What is the benefit
of that, and how would you get widespread agreement on it?  And why would it
be more trouble free?

> <Class ID="Animal">
>   <label>Animal</label>
>   <comment>
>     This class of animals is illustrative of a number of ontological
> idioms.
>   </comment>
> </Class>
> <Class ID="Male">
>   <subClassOf resource="#Animal"/>
> </Class>
> <Class ID="Female">
>   <subClassOf resource="#Animal"/>
>   <disjointWith resource="#Male"/>
> </Class>
> A benefit of this simplified syntax would be 1) that more people would be
> able to write ontologies and 2) that parsing DAML constructs would be a
> very trivial process

The only simplification I see is not writing prefixes, and you give up
knowing exactly what is intended by the various constructs and names.  You
also give up the ability to easily call upon other systems (e.g.,
jsmith:label vs. rdfs:label) when they might be useful.


Received on Wednesday, 28 November 2001 20:43:28 UTC

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