From: Dan Connolly ([email protected])
Date: 01/04/01
Er... where did all this syntax stuff in
DAML+OIL reference description
http://www.daml.org/2000/12/reference.html#Header
Wed, 03 Jan 2001 18:45:23 GMT
come from? DAML+OIL syntax is just RDF syntax, no? Our
spec just specifies the semantics of some terms, no?
i.e. we're just specifying what inferences we license
based on our terms (and our understanding of the
RDF and RDF terms) no?
e.g.
A DAML+OIL ontology consists of a header, followed by zero or
more class elements, property elements, axioms and instances.
When did we decide to limit ontologies to one <Ontology> element
at the top?
When did we decide to limit the contents of the Class element
ala
"A Class element [...] contains
zero or more subClassOf elements
...
"
???
DAML syntax is just RDF syntax. We define the *semantics* of
some terms, but we don't constrain the syntax at all.
That's my understanding.
These are perfectly good DAML+ONT ontologies, no?
########
<!-- an empty ontology is just fine, no? -->
<rdf:RDF
xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
/>
########
<rdf:RDF
xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
xmlns:fruit="http://example.org/2001/fruit#">
<!-- we can use arbitrary RDF classes for typedNode element names, no?
-->
<fruit:Bannana>
<!-- and arbitrary RDF property names for property elements, no? -->
<fruit:size>6"</fruit:size>
</fruit:Bannana>
</rdf:RDF>
########
<rdf:RDF
xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#"
xmlns:daml="http://www.daml.org/2000/12/daml+oil#"
xmlns:fruit="http://example.org/2001/fruit#"
>
<rdfs:TransitiveProperty ID="ex3">
<!-- even RDF/DAML properties can have arbitrary claims
made about them; claims using terms we don't define, no?
-->
<fruit:flavor>yummy</fruit>
</rdfs:TransitiveProperty>
<rdf:Description ID="Cups">
<!-- this is another way to say that something is
a class, no? -->
<rdf:Type resource="http://www.w3.org/2000/01/rdf-schema#Class"/>
</rdf:Description>
</rdf:RDF>
########
If we actually want to specify syntax, I think the way to do it
is with an XML Schema (this is how I think we should integrate
concrete types, too; sorry my proposal on that is so late.)
RDF Syntax: An XML Schema Approach
in progress Aug 2000
http://www.w3.org/2000/07/DAML-0-5-syntax
btw... Something I noticed while reading:
the schema ($Id: daml+oil.daml,v 1.2 2001/01/02 19:15:55 mdean Exp $)
has
<rdfs:Class rdf:ID="Thing">
but later...
<subPropertyOf resource="#equivalentTo"/>
i.e. subPropertyOf is short for
http://www.daml.org/2000/12/daml+oil#subPropertyOf
but rdfs:Class is short for
http://www.w3.org/2000/01/rdf-schema#Class
Any particular reason not to be more consistent?
i.e. use rdfs: for all the things that are in RDFS?
--
Dan Connolly, W3C http://www.w3.org/People/Connolly/
office: tel:+1-913-491-0501
pager: mailto:[email protected]
(put return phone number in from/subject)
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