theorem
  for F being Function of [:D,D9:],E holds F[:](<*>D,d9) = <*>E
proof
  let F be Function of [:D,D9:],E;
  reconsider r = F[:](<*>D,d9) as FinSequence of E by Th81;
  len(<*>D) = 0;
  then len r = 0 by Th82;
  hence thesis;
end;
