/**
 * 飯高 茂「Prologで作る数学」 p.134
 */
 
permutation([], []).
permutation([A|X1], Y) :- delete(Y, A, Y1), permutation(X1, Y1).
 
delete([A|X], A, X).
delete([B|X], A, [B|Y]) :- delete(X, A, Y).
 
program :- 
    findall((X,Y), delete([1,2,3], X, Y), Bag),
    print(Bag).