cyclical subclass/property statements

From: Ian Horrocks (
Date: 01/07/01


Last week we discussed the issue of whether daml+oil should reflect
RDFS as it is or RDFS as we would like it to be/believe it will be. In
this regard, I mentioned that if we don't take the acyclicity of
subClass seriously, we could strengthen the statements about
equivalent names in the daml+oil namespace. e.g., instead of saying

<rdfs:Class rdf:ID="Literal">
  <sameClassAs rdf:resource=""/>

we could add:

<rdfs:Class rdf:about="">
  <sameClassAs rdf:resource="#Literal"/>

or perhaps:

<rdfs:Class rdf:about="">
  <rdfs:subPropertyOf rdf:resource="#Literal"/>

In other words, we can assert subClass/property in both directions.

Having thought some more about this, I can't really see the benefit
and so I am not sure that we should do it. It doesn't help
daml+oil-aware processes as they already understand the semantics of
the sameClassAs property, and it will only help RDFS-aware processes
if they are smart enough to work out that two subs make an
equivalent. It might be more likely to confuse/crash RDFS

Perhaps we could briefly (re)discuss this on Tuesday before I make any


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