% (1)

sublista([],_).
sublista([H|A],[H|B]) :- sublista(A,B).
sublista(A,[_|B]) :- sublista(A,B).

% (2)

conta([],[]).
conta([H|T],R) :-
	conta(T, R1),
	coloca(H,R1,R).

coloca(A,[],[[A,1]]).
coloca(A, [ [A,N] | R ], [ [A,N1] | R ]) :- !, N1 is N+1.
coloca(A, [H|L], [H|R]) :- coloca(A,L,R).

% (3)

perm(L,R) :- findall(X,geraperm(L,X),R).

geraperm([],[]).
geraperm([H|T],R) :-
	geraperm(T,R1),
	select(H,R,R1).