%------------------------------------------------------------------------
% Program for which mostly everything is undefined.
%
%     Subgoals | Answers
%--------------------------------------------------
%	p(X)   | p(a)	[<q(X,Y),q(a,Y),q(a,Y)>]
%	q(X,Y) | q(a,Y)	[<tnot(s)>]
%	r(X)   | r(b)	[]
%	s      | s	[<tnot(t)>]
%	t      | t	[<tnot(s)>]
%------------------------------------------------------------------------

:- table p/1, q/2, r/1, s/0, t/0.

p(X) :- q(X,Y), r(Y).

q(a,_) :- tnot(s).

r(b).

s :- tnot(t).
t :- tnot(s).

%------------------------------------------------------------------------

test :- p(_X), fail.
test.