W3C home > Mailing lists > Public > semantic-web@w3.org > September 2006

Re: Individuals with more than one rdf:type

From: Frank Manola <fmanola@acm.org>
Date: Thu, 21 Sep 2006 19:28:46 -0400
Message-ID: <4513202E.8060901@acm.org>
To: Marja Koivunen <marja@annotea.org>
CC: Jon Hanna <jon@hackcraft.net>, David Navarro Arnao <dnavarro@isoco.com>, ben syverson <w3@likn.org>, semantic-web@w3.org

Marja Koivunen wrote:
> 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 :-).

Marja--

I could say that what you would have wouldn't be a "book" ("a number of 
sheets of paper, parchment, etc. with writing or printing on them"), it 
would be a motor vehicle with the *contents* of a book written on it. 
Then you could say that yes it is a book, it just has very big pages, 
namely the doors and the covers of the engine and luggage compartments, 
  you turn the pages by opening and closing them, and speed-reading can 
be measured in kph :-)  Also, if the original book had pictures, and 
they were also reproduced on the motor vehicle, presumably you could say 
that the motor vehicle is not only the book, but also the motion 
picture!  And so on.

However, keep in mind that my original comment wasn't that it would be 
*impossible* to concoct a situation in which an instance was (or, at 
least, could be argued to be) both a book and a motor vehicle, but that 
it might appear weird ("strikingly odd").  So I agree that it would be 
"no problem" to write the contents of a book on a motor vehicle, of 
course modulo things like finger-cramp, copyright issues, field sobriety 
tests conducted by inquisitive police officers ("Oh this is a book is 
it?  Do you have a license to drive books?  How many beers have you had 
anyway?"), etc.  But don't you think that writing a book on a motor 
vehicle is reasonably described as "strikingly odd"?

> 
> 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.

Sure, but my original point was that not only can RDF describe instances 
that have multiple types that seem to make sense in combination, as in 
these Annotea cases, but it can also describe instances that have 
multiple types that don't seem to go together.

--Frank
Received on Thursday, 21 September 2006 23:20:21 UTC

This archive was generated by hypermail 2.3.1 : Tuesday, 1 March 2016 07:41:53 UTC