Re: P.S. Re: Model Theory

From: Enrico Motta <>
Subject: Re: P.S. Re: Model Theory
Date: Mon, 7 Jan 2002 11:37:05 +0000

> 2) Some 'KR programming cliches' are useful in practice but are 
> tricky to formalise in a model theory (e.g., reification, defaults, 
> etc..). Now, taking a 'pragmatic' approach means that we do not 
> <<automatically>> discard these constructs, simply because we do not 
> know how to write the model theory.  Maybe an alternative approach to 
> specification can be used, or maybe we simply state algorithmically 
> how intepreters will deal with these constructs. 

If you (or someone else) can come up with a workable specification for
these constructs, then I would be very happy.  The problem lies in
determining what constructs mean, whether it be via a model theory, via a
proof theory, via axiomatization, or even via some more-operational
mechanism.  In the absence of a workable specification for a construct,
e.g, reification, and, moreover, one that has good connection to the
intended meaning of the construct, I am unwilling to include the construct
in a representation language.

> - Enrico


PS:  Actually defaults do have several decent specifications.  However, the
specifications have very bad computational properties, which make them
problematic in a *useful* representation language.

Received on Monday, 7 January 2002 07:59:06 UTC