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    ELECTRONIC NEWSLETTER ON  REASONING ABOUT ACTIONS AND CHANGE        
Issue 99021             Editor: Erik Sandewall             11.8.1999
         Back issues available at http://www.etaij.org/rac/
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                    *********  TODAY  *********

Tom Costello and John McCarthy have submitted an article with the title
'Useful Counterfactuals' to the ETAI.


              *********  ETAI PUBLICATIONS  *********

                    ---  RECEIVED ARTICLES  ---

        ========================================================
        |  AUTHOR: Tom Costello and John McCarthy
        |  TITLE:  Useful Counterfactuals
        |  PAPER:  http://www.ida.liu.se/ext/epa/cis/1999/012/tcover.html
        |  [provisional]
        |  REVIEW: http://www.ida.liu.se/ext/etai/ra/rac/021/
        ========================================================

                             ABSTRACT 

Counterfactual conditional sentences can be useful in
artificial intelligence.  In particular, they allow reasoners to
learn from experiences that they did not quite have.  The truth of a
counterfactual and the conclusions that can be drawn from a
counterfactual are theory dependent, and different theories are
useful in different circumstances.
  
A simple class of useful counterfactuals involves a change of one
component of a point in a space provided with a cartesian product
structure.  We call these cartesian counterfactuals.  Cartesian
counterfactuals can be modeled by assignment and contents functions
as in program semantics.  We also study the more general
tree-structured counterfactuals.


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