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RE: Reflexivity and antisymmetry uses cases?

From: Lansing, Jeff <jlansing@systechnologies.com>
Date: Wed, 17 Jan 2007 08:51:08 -0800
Message-ID: <0924D8C9ADE6C04D9FA73CC47C0FA8E402CA0FC5@SYSSDEX.syys.com>
To: <public-owl-dev@w3.org>



From: public-owl-dev-request@w3.org on behalf of Dave Reynolds
Sent: Wed 1/17/2007 4:02 AM
To: Gerd Wagner
Cc: public-owl-dev@w3.org
Subject: Re: Reflexivity and antisymmetry uses cases?

Gerd Wagner wrote:
>> 3) A certain skirting around the issue of how RDF and OWL semantics 
>> differ from the usual database view of the world. Domain and Range 
>> are a constant source of confusion. Open world assumptions also 
>> makes, e.g. cardinality restrictions, not behave the way one would 
>> expect them to. I think the choice of open world assumption is well 
>> motivated,
> Is it really (in all cases)?
> I don't think that there was ever any deliberate design decision
> in favor of the "open world assumption" (OWA) versus the CWA in
> the making of OWL. The OWA is just in the baggage of classical
> mathematical logic, so if you stick to that formalism, you get
> it for free (without having any chance to reject or weaken it).

In RDF OWA was a deliberate design decision based on the intended use
case of representing distributed web information. On the web you expect
to often have partial information from one source and never know what
other assertions might be "out there" that you haven't yet taken into
account but might do so in the future.

Isn't there a difference between reasoning based on OWA and reasoning based on not knowing other assertions not yet taken into account but possibly taken into account in the future?

(Whatever that is; sounds like those famous "unknown unknows" to me.)

Received on Wednesday, 17 January 2007 16:54:25 UTC

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