reserve i for Nat, x,y for set;
reserve S for non empty non void ManySortedSign;
reserve X for non-empty ManySortedSet of S;

theorem
  for a1,a2,a3,a4,a5,a6 being object holds
  rng <*a1,a2,a3,a4,a5,a6*> = {a1,a2,a3,a4,a5,a6}
  proof
    let a1,a2,a3,a4,a5,a6 be object;
    thus rng <*a1,a2,a3,a4,a5,a6*>
    = rng <*a1,a2,a3,a4,a5*> \/ rng <*a6*> by FINSEQ_1:31
    .= {a1,a2,a3,a4,a5} \/ rng <*a6*> by CIRCCMB3:14
    .= {a1,a2,a3,a4,a5} \/ {a6} by FINSEQ_1:39
    .= {a1,a2,a3,a4,a5,a6} by ENUMSET1:15;
  end;
