% File 'publish'
% Publishing Papers ("Nonmonotonic Causal Theories," Figure 9)

:- sorts
  class; number.

:- objects
  conference, journal      :: class;
  1..100                   :: number. 

:- variables
  N                        :: number.

:- constants
  hasPublications,
  hasJournalPublications,
  hasLongPublications      :: inertialFluent;
  publish                  :: exogenousAction;
  kind                     :: attribute(class) of publish;
  length                   :: attribute(number) of publish.


constraint hasJournalPublications ->> hasPublications.
constraint hasLongPublications ->> hasPublications.

publish causes hasPublications.
publish causes hasJournalPublications if kind=journal.
publish causes hasLongPublications if length>30.


:- query 
maxstep :: 3;
0: -hasPublications;
0: publish, kind=conference, length=6;
1: publish, kind=journal, length=20;
2: publish, kind=journal, length=40.