% it is a crime to sell weapons to hostile nations:
criminal(X):-american(X),weapon(Y),sells(X,Y,Z),hostile(Z).
% Nono ... has some missiles,
owns(nono,m1).
missile(m1).
% all of its missiles were sold to it by Colonel West
sells(west,X,nono) :- missile(X), owns(nono,X).
% Missiles are weapons
weapon(X) :- missile(X).
% An enemy of America counts as ‘‘hostile’’:
hostile(X) :- enemy(X,america).
% The country Nono, an enemy of America ...\al
enemy(nono,america).
% West, who is American ...\al
american(west).