reserve X,Y,z,s for set, L,L1,L2,A,B for List of X, x for Element of X,
  O,O1,O2,O3 for Operation of X, a,b,y for Element of X, n,m for Nat;
reserve F,F1,F2 for filtering Operation of X;
reserve i for Element of NAT;

theorem Th56:
  for A being FinSequence holds max# A <= len A
  proof
    let A be FinSequence;
    for a being set holds #occurrences(a,A) <= len A by Th54;
    hence max# A <= len A by Def23;
  end;
