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Re: [BLD] comments on BLD draft

From: Michael Kifer <kifer@cs.sunysb.edu>
Date: Tue, 15 Apr 2008 14:45:12 -0400
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: <4798.1208285112@cs.sunysb.edu>


If you mean that =, #, ## with external terms should be allowed to appear
in the rule bodies then yes, they should. I thought you wanted to assert
equalities among the externals. I agree that BLD makes contradictory
statements about them.

Actually, I found a number of other problems with the syntax. For instance,
atomic external formulas were not well-defined.  I made the required
changes now (incl. fixing the contradictions about external terms, which
you noticed).

If Sandro could stealthily replace the published version -- would be good.
Not a very big deal though.


	--michael  

> Michael Kifer wrote:
> >>
> >>No, I meant: in "# Equality terms. If t and s are simple, positional, or 
> >>named-argument terms then t = s is an equality term.", shouldn't t and s 
> >>be allowed to be external terms as well (same for #, ## and frame)?
> >>
> > I think that equality among external terms should *not* be allowed, since
> > it cannot be tested anyway (definition of an external term is a black box
> > to a rif document, by definition).
> 
> It can be tested by the consumer: if it could not, a RIF document that 
> contained external calls would be useless, wouldn't it?
> 
> > For instance, one could write External(t) = External(s)
> > but these two externals' black boxes might not be equal, and the reasoner
> > will have no way of testing that.
> 
> I can see that equality or classification terms with external terms may 
> be a problem in the head; but in the body?
> 
> Christian
> 
> 
Received on Tuesday, 15 April 2008 18:45:47 GMT

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