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RE: firts and rdf:rest as functional property

From: Michael Schneider <schneid@fzi.de>
Date: Fri, 20 Mar 2009 17:44:22 +0100
Message-ID: <0EF30CAA69519C4CB91D01481AEA06A0011D9B04@judith.fzi.de>
To: Reto Bachmann-Gmür <reto.bachmann@trialox.org>
Cc: "Semantic Web" <semantic-web@w3.org>, "Bijan Parsia" <bparsia@cs.man.ac.uk>
Oops, stupid me!

>From: Michael Schneider

>(1) Lists should terminate, but there is no enforcement of a final
>rdf:nil:
>
>      A -> B -> C   // no NIL

[...]

>(In (1), the list could be terminated by anything else but rdf:nil, so
>the min-1 axiom would be satisfied for rdf:rest).

This case does not need to be considered: rdf:List must not be restricted to
be min-1(rdf:rest). Otherwise lists could never terminate (looping would be
ok, though). In particular, rdf:nil would then have a rdf:rest property,
with another instance of rdf:List as its value, and so on. 

One could solve the particular problem with rdf:nil having a successor by
only restricting the class

  rdf:List \ { rdf:nil } 

to min-1(rdf:rest). But I guess things are starting to get a bit
complicated... :)

Michael
 
--
Dipl.-Inform. Michael Schneider
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Received on Friday, 20 March 2009 16:56:00 GMT

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