- From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
- Date: Mon, 07 Jan 2002 07:57:44 -0500
- To: e.motta@open.ac.uk
- Cc: www-webont-wg@w3.org
From: Enrico Motta <e.motta@open.ac.uk> 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 peter 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