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Re: Issue rdfms-boolean-valued-properties

From: Graham Klyne <Graham.Klyne@MIMEsweeper.com>
Date: Wed, 14 Nov 2001 21:00:14 +0000
Message-Id: <5.1.0.14.2.20011114205020.0452b1c0@joy.songbird.com>
To: Brian McBride <bwm@hplb.hpl.hp.com>
Cc: rdf core <w3c-rdfcore-wg@w3.org>
I don't oppose the proposal, but I'd like to note that there's an 
alternative approach, also not requiring any new vocabulary.

A Boolean valued property could be regarded as equivalent to a monadic 
predicate;

    e.g.  (IsLikeThis(SomeResource) == TRUE)  <=>  IsLikeThis(SomeResource)

Treatments of typed logic that I have read (notably Sowa's book Knowledge 
Representation) suggest that a type is just a shorthand for a value that 
satisfies a monadic predicate:

     (FORALL (x:integer) (EXISTS (y:integer) y > x))

is equivalent to:

     (FORALL (x) integer(x) => (EXISTS (y) integer(y) AND y>x))

Which leads to the idea that Boolean valued properties are simply monadic 
predicates which can be represented as types:

     X rdf:type integer .

asserts the truth of:

     integer(X)

#g
--

At 07:05 PM 11/14/01 +0000, Brian McBride wrote:
>Issue
>
>   http://www.w3.org/2000/03/rdf-tracking/#rdfms-boolean-valued-properties
>
>requests a standard way to represent boolean valued properties and 
>suggests the definition of rdf:is and rdf:isNot properties to meet this need.
>
>Propose that as schema data types define a boolean data value, this issue 
>be merged with:
>
>   http://www.w3.org/2000/03/rdf-tracking/#rdfs-xml-schema-datatypes
>
>Brian

------------------------------------------------------------
Graham Klyne                    MIMEsweeper Group
Strategic Research              <http://www.mimesweeper.com>
<Graham.Klyne@MIMEsweeper.com>
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Received on Wednesday, 14 November 2001 16:10:59 EST

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