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Re: Define a property to have an EMPTY range ... use owl:Nothing?

From: Richard H. McCullough <rhm@cdepot.net>
Date: Wed, 14 May 2003 07:53:05 -0700
Message-ID: <000b01c31a28$89789160$bd7ba8c0@rhm8200>
To: "Roger L. Costello" <costello@mitre.org>, <www-rdf-interest@w3.org>
Cc: "Costello,Roger L." <costello@mitre.org>

1. I would avoid using "Nothing".  Philosophically, it is not a valid
concept.
2. The basic question is -- what is the "opposite" or "complement" of a
secret document.
In other words, either
    document has secret property
or
    document does not have secret property
I have used two different schemes for this situation
    either document has secret or document has not secret  (property is "not
secret")
    either document has secret=true or document has secret=false

P.S. For this particular example, the best characterization is clearly
document has security classification = secret.
with other values being unclassified, confidential, top secret, ...
Typical English usage would be this definition
    a secret document is a document with security classification = secret.

Dick McCullough
knowledge := man do identify od existent done;
knowledge haspart proposition list;

----- Original Message ----- 
From: "Roger L. Costello" <costello@mitre.org>
To: <www-rdf-interest@w3.org>
Cc: "Costello,Roger L." <costello@mitre.org>
Sent: Wednesday, May 14, 2003 7:30 AM
Subject: Define a property to have an EMPTY range ... use owl:Nothing?


>
> Hi Folks,
>
> Oscar Corcho sent me an interesting idea - use owl:Nothing to represent
> EMPTY, e.g.,
>
>     <rdf:Property rdf:ID="secret">
>         <rdfs:domain rdf:resource="#Document"/>
>         <rdfs:range rdf:resource="&owl;Nothing"/>
>     </rdf:Property>
>
> A very interesting idea!  Are there any drawbacks to this?  Does it
> achieve the desired result of requiring secret to have an EMPTY range,
> e.g.,
>
>     <Document>
>         <secret/>
>     </Document
>
> /Roger
Received on Wednesday, 14 May 2003 10:53:14 GMT

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