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Re: Two further review comments on S&AS

From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
Date: Tue, 25 Mar 2003 10:51:55 -0500 (EST)
Message-Id: <20030325.105155.106404917.pfps@research.bell-labs.com>
To: jjc@hplb.hpl.hp.com
Cc: www-webont-wg@w3.org

From: "Jeremy Carroll" <jjc@hplb.hpl.hp.com>
Subject: Two further review comments on S&AS
Date: Tue, 25 Mar 2003 14:24:57 +0100

> 
> 
> I have two more comments left over from January
> 
> A: Side condition
> 
> This
> [[
> Properties that 1/ are specified as being transitive, 2/ have an inverse
> property specified as being transitive, or 3/ have a sub-property (direct or
> indirect) or an inverse of such a sub-property specified as being transitive
> cannot participate in cardinality restrictions and cannot be specified as
> functional or inverse-functional.
> ]]
> is a big improvement but omits the following cases
> 
> 1:
> 
> ObjectProperty( p inverseOf(invp) Functional )
> ObjectProperty( invp )
> ObjectProperty( q super(invp) Transitive )
> 
> 2:
> 
> ObjectProperty( q Functional )
> ObjectProperty( p super(q) inverseOf(invp) )
> ObjectProperty( invp )
> ObjectProperty( q super(invp) Transitive )
> 
> Peter, if you would like me to suggest a minor mod to the text I can work on
> it for tomorrow - I can't think of anything off the top of my head.

I changed to

An object property is <em>complex</em> if 
1/ it is specified as being functional or inverse-functional, 
2/ there is some cardinality restriction that uses it,
3/ it has an inverse that is complex, or
4/ it has a super-property that is complex.
Complex properties cannot be specified as being transitive.

which should cover all the bases (cases?).

> B: Literal
> 
> The following entailment holds according to the direct semantics but not in
> OWL Full.
> 
> <p> rdf:type owl:DatatypeProperty .
> <p> rdfs:range rdfs:Literal .
> 
> entails
> 
> rdfs:Literal rdf:type rdfs:Datatype .
> 
> 
> Suggest, simply prohibit the triple
> 
> rdfs:Literal rdf:type rdfs:Datatype .
> 
> from OWL DL (in section 4).

The problem here is that RDF datatyping is broken.  The best way (in my
opinion) of fixing it would make rdfs:Literal belong to rdfs:Datatype in
RDFS.   I'm still hoping that this will happen.

> (My last recycled comments will be stylistic/editorial and so could be
> ignored).
> 
> Jeremy

peter
Received on Tuesday, 25 March 2003 10:53:22 GMT

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