******************************************************************** ELECTRONIC NEWSLETTER ON REASONING ABOUT ACTIONS AND CHANGE Issue 98024 Editor: Erik Sandewall 4.3.1998 Back issues available at http://www.ida.liu.se/ext/etai/actions/njl/ ******************************************************************** ********* TODAY ********* Today, a question by Francois Levy to the ETAI submitted article by Kakas and Miller. ********* ETAI PUBLICATIONS ********* --- DISCUSSION ABOUT RECEIVED ARTICLES --- ======================================================== | AUTHOR: Antonis Kakas | TITLE: Reasoning about Actions, Narratives and Ramification ======================================================== -------------------------------------------------------- | FROM: Francois Levy -------------------------------------------------------- Dear Antonis and Rob Here are two late questions about your paper. First, according to your view of ramifications, fluents can be initiated/terminated in two ways: either when an event occurs, or due to changing fluents in a constraint. The formal difference is that a fluent changing its value is not by itself an event. Do you consider it to rely on an ontological difference -- i.e. in the process of modeling the real world, two kinds of objects of different nature have to be considered: events on the one side, (instantly) changing fluents on the other one. Or do you consider both similar, and make a difference on a purely technical ground (trigered events don't work to render this if the time line is dense)? Second, as far as I understand, your predicate 'Whenever' embeds both a domain constraint and a notion of influence, in Michael Thielscher's sense in his AI97 paper. The domain constraint is what you call the static view -- i.e. 'Whenever' being replaced by a material implication. The influence information is: in the formula 'L Whenever C', only L can be initiated, so one domain constraint yields as many 'Whenever' formulas as fluents can be influenced in it. But Thielscher's Influence predicate is binary, and of course his cause --> effect propagation is a different technique. I tried shortly some example, and could'nt find a difference in the flow of causality. Do you agree with these remarks ? And do you believe that some formal correspondance could be established between your two formalisms ? Best Regards Francois ******************************************************************** This Newsletter is issued whenever there is new news, and is sent by automatic E-mail and without charge to a list of subscribers. To obtain or change a subscription, please send mail to the editor, erisa@ida.liu.se. Contributions are welcomed to the same address. Instructions for contributors and other additional information is found at: http://www.ida.liu.se/ext/etai/actions/njl/ ********************************************************************