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Re: [BLD] Frame without slot/value pair?

From: Michael Kifer <kifer@cs.sunysb.edu>
Date: Fri, 04 Jan 2008 22:18:53 -0500
To: Christian de Sainte Marie <csma@ilog.fr>
Cc: "Boley, Harold" <harold.boley@nrc-cnrc.gc.ca>, RIF WG <public-rif-wg@w3.org>
Message-ID: <11606.1199503133@cs.sunysb.edu>


> 
> Michael Kifer wrote:
> > 
> > [...]  Formulas like t[] are also useful. If they are allowed, their
> > semantics is that the object t exists (without testing any of its
> > properties).
> 
> Hmmm. I wonder how useful it is really.
> 
> In order to check the existence of object t, you have to denote it in 
> some way: How do you denote an object without either asserting or 
> checking its existence already in the process (thus removing any need to 
> check it further)?

What does one have to do with the other??

It is like asking, "why is it useful to test that a table is not empty?
Shouldn't one first create a table and put tuples into it?


> Actually, the only use I found for a formula like t[] is to allow the 
> retraction of an individual without having to allow retracting TERMs as 
> well as ATOMICs (in RIF-PRD). But that's a different can of worms...

You found a use in what context? In PRD or BLD? In logic programming-style
dialects this is undoubtedly useful.


	--michael  


> Christian
> 
> 
> 
Received on Saturday, 5 January 2008 03:19:02 GMT

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