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Re: plural vs singular properties (a proposal)

From: Eyal Oren <eyal.oren@deri.org>
Date: Mon, 23 Apr 2007 13:52:27 +0100
To: semantic-web@w3.org
Message-id: <20070423125227.GA23787@localhost>

On 04/23/07/04/07 10:12 +0100, David Price wrote:
>
>Seems like the singular property is closer to the semantics - the relationship 
>is between a Person who is a parent and a Person who is a child, not a Person 
>who is a parent of a SetOfPerson who are children. Contracts that with a 
>Person who is the coach of a SetOfPerson who are a football team.
>
>I'd also suggest that letting how OO programming systems work influence 
>accurate semantics may lead to mistakes. OO programming languages are largely 
>about shared behaviour, not shared semantics (e.g. the "is circle kind of 
>ellipse" debate).
With respect to OO and Semantic Web, you may be interested in our upcoming 
WWW paper "ActiveRDF: Object-Oriented Semantic Web Programming" [1] which 
also discusses some interesting differences between OO and RDFS/OWL 
semantics.

Now, for Sandro's proposal, in ActiveRDF properties return either singular 
values (e.g. a foaf:Person) or an Array of values, depending on the number 
of triples that carry that property for the given subject. Since we're 
using a dynamic language such multi-typing is no problem:

  # in one case we might return a single value
  eyal.foaf::knows ==> renaud
  
  # but with a different data set an array
  eyal.foaf::knows ==> [renaud, armin, stefan]

  # if you as programmer want an array in any case you can ask for it
  eyal.foaf::all_knows ==> [renaud]

I personally find this quite ok, without the need for plural properties?

But I have to say, I have also often wondered about the choice and 
redundancy between style 1 and style 2, so in principle I like "binding" 
them together. I would in any case support your 'best practice' that 
content providers should avoid style 2 unless necessary. 

 -eyal

[1] http://www2007.org/paper272.php
Received on Monday, 23 April 2007 12:52:20 GMT

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