1:- use_module(library(scasp)).    2
    3validate(L) :-
    4    findall(X, member(X,L), LL),
    5    LL = L.
    6
    7member(X1, [X2|_]) :- X1 #= X2.
    8member(X, [_|R]) :- member(X, R).
    9
   10% ?- validate([1,2,3]).