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Re: [PRD] Proposal for object representation (and ACTION-592 complete)

From: Christian de Sainte Marie <csma@ilog.fr>
Date: Mon, 09 Mar 2009 20:59:42 +0100
Message-ID: <49B5752E.5040702@ilog.fr>
To: kifer@cs.sunysb.edu
CC: RIF WG <public-rif-wg@w3.org>

Michael Kifer wrote:
> these things are called path expressions and they are not necessarily
> single-valued. For instance, FLORA-2 uses them alongside the frames,
> and they are simply shortcuts for some forms of conjunctions of frames.

I have taken the action to rework my proposal to separate the issues of single-valued attributes, and path location.

But that supposes that I understand how path locations can be multi-valued: as much as I understand that, as atomic assertions, frames that associate different values to the same object-attribute pair can be true at the same time; as much I cannot understand how a path expression, as a basic term, can represent more than one value. Actually, dealing with single-valued attributes in a way that seemed intrinsically appropriate for them - which frames are not - and that is quite usual in object-oriented languages was the main reason for my proposal.

I mean, other basic terms, such as a constant symbol, a variable, or a ground function call, represent, cannot represent but a single value: how can a path expression, as a basic term, represent more than one? Of course, it can be set-valued, but it still has a single value, which is the set.

Can you please clarify? An example would, also, certainly help me understand better what you mean.


Received on Monday, 9 March 2009 20:00:33 UTC

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