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Re: Individuals with more than one rdf:type

From: Marja Koivunen <marja@annotea.org>
Date: Thu, 21 Sep 2006 18:23:41 -0400
Message-ID: <451310ED.8040005@annotea.org>
To: Frank Manola <fmanola@acm.org>
CC: Jon Hanna <jon@hackcraft.net>, David Navarro Arnao <dnavarro@isoco.com>, ben syverson <w3@likn.org>, semantic-web@w3.org

Frank Manola wrote:
> Jon--
> I didn't say this wasn't "valid" (although technically I don't think 
> "valid" is the right concept here, since we're talking about 
> statements rather than an argument), and I did say it was legal RDF 
> (i.e., grammatically).  However, I still think that an instance being 
> both a Book and a MotorVehicle appears "weird" ("strikingly 
> odd"--Webster's New World Dictionary).  That this idea is "strikingly 
> odd" was one of the reasons for choosing it as an example in the first 
> place!
If I write the contents of a book (e.g. the Zen and the art of 
motorcycle maintenance) on a motor vehicle it will be a motor vehicle 
and a book and in addition also some kind of art. So I see no problems 
in doing this :-).

Annotea actually uses this for annotations. We have type Annotation and 
some sample annotation subtypes e.g. Advise, Change, Comment, Example, 
Explanation, Question, SeeAlso. And the user can define more subtypes. 
Each annotation object is of type Annotation and of some annotation subtype.

The bookmark objects on the other hand are tied to categories with topic 
objects (tags) with hasTopic property.

> --Frank
> Jon Hanna wrote:
>> Frank Manola wrote:
>>> For example, Section 5.2 has an example of declaring domains which 
>>> results in you having to conclude that an instance is both a Book 
>>> and a MotorVehicle.  This may appear weird, but it's perfectly legal 
>>> RDF.
>> It's not that weird. "The collected works of Shakespeare is both a 
>> book and a motorised vehicle" is a perfectly valid sentence. It's 
>> nonsense, but that's not a matter for the rules of grammar to 
>> resolve. So it is too with RDF.
Received on Thursday, 21 September 2006 22:24:56 UTC

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