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asymmetric VS non-symmetric

From: Antoine Zimmermann <antoine.zimmermann@deri.org>
Date: Fri, 31 Jul 2009 12:21:29 +0100
Message-ID: <4A72D3B9.3040609@deri.org>
To: 'W3C OWL Working Group' <public-owl-wg@w3.org>
Dear all,

Until today, I did not look at the semantics of AsymmetricProperty 
because the word was familiar enough to me to intuitively understand it. 
I was however wrongly assuming that the word was used to denote 
non-symmetric. From a linguistic perspective, asymmetry is a lack or 
absence of symmetry. Some mathematical texts use "asymmetric" to simply 
mean "not symmetric".

I am aware that "asymmetric relation" is often used in mathematics to 
denote "strongly asymmetric relation", i.e., no pairs of elements are 
related in a bidirectional (symmetric) way. While it is perfectly ok 
that OWL2 defines AsymmetricProperties the way it does, I am surprised 
not to find *any* remark, neither in the formal specs, nor in the UFDs, 
nor in the mailing list archives, about the fact that AsymmetricProperty 
is not the complement of SymmetricProperty.

I am sure that other people are understanding asymmetry in the same way 
as I did, so I'd suggest adding a small sentence in the Primer (Sect.6.1 
[1]) and NF&R (Sect.2.2.3 [2]) stating that "asymmetric" is not the 
negation of "symmetric". Since the UFDs are still in LC, this should be 
addressed somehow.

[1] 
http://www.w3.org/TR/2009/WD-owl2-primer-20090421/#Property_Characteristics
[2] 
http://www.w3.org/TR/2009/WD-owl2-new-features-20090421/#F6:_Reflexive.2C_Irreflexive.2C_and_Asymmetric_Object_Properties

Regards,
-- 
Antoine Zimmermann
Post-doctoral researcher at:
Digital Enterprise Research Institute
National University of Ireland, Galway
IDA Business Park
Lower Dangan
Galway, Ireland
antoine.zimmermann@deri.org
http://vmgal34.deri.ie/~antzim/
Received on Friday, 31 July 2009 11:22:11 GMT

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