% AILog code to demonstrate default reasoning.

% This is the code discussed in Example 5.30 of Section 5.5.1 of Poole
% and Mackworth, Artificial Intelligence: foundations of computational
% agents, Cambridge, 2010.

% Copyright (c) David Poole and Alan Mackworth 2009. This program
% is released under GPL, version 3 or later; see http://www.gnu.org/licenses/gpl.html

% To run this in AILog, you should put it in the same directory as AILog and then call
% load 'bronchitis.ail'.

bronchitis <- influenza & influenzaCausesBronchitis.
bronchitis <- smokes & smokingCausesBronchitis.
coughing <- bronchitis.
wheezing <- bronchitis.
fever <- influenza.
soreThroat <- influenza.
false <- smokes & nonsmoker.
assumable smokes, nonsmoker, influenza.
assumable influenzaCausesBronchitis,  smokingCausesBronchitis.

% The following makes sure that only consistent explanations are found:
create_nogoods.

% Try the following queries:
% ask wheezing.
% ask wheezing & fever.
% ask wheezing & nonsmoker.