:- object(rational, implements(comparingp)). :- info([ authors is 'Paulo Moura', version is 1.0, date is 2000/4/22, comment is 'Implements comparison between rational numbers represented as Num/Den.']). N1/D1 < N2/D2 :- {N1*D2 < N2*D1}. N1/D1 =< N2/D2 :- {N1*D2 =< N2*D1}. N1/D1 > N2/D2 :- {N1*D2 > N2*D1}. N1/D1 >= N2/D2 :- {N1*D2 >= N2*D1}. N1/D1 =:= N2/D2 :- {N1*D2 =:= N2*D1}. N1/D1 =\= N2/D2 :- {N1*D2 =\= N2*D1}. :- end_object.