% File 'example2-smodels': A graph coloring program
% as an input file for smodels.
% Copy lparse and smodels from directory /projects/tag/smodels/current/sun/ .
% Command line: 'lparse < example2-smodels | smodels'.

node(0..5).

col(r).
col(b).
col(g).

edge(0,1).
edge(0,2). 
edge(1,2).
edge(1,3).
edge(2,4).
edge(3,4).
edge(3,5).
edge(4,5).

color(X,r) | color(X,b) | color(X,g) :- node(X).

% Alternative:
% 1 {color(X,C) : col(C)} 1 :- node(X).

:- edge(X,Y), col(C), color(X,C), color(Y,C).

hide node(X).
hide edge(X,Y).
hide col(C).