theorem
  for f being (V,A)-NonatomicND-yielding FinSequence holds
  n in dom f implies f.n is NonatomicND of V,A
  proof
    let f be (V,A)-NonatomicND-yielding FinSequence;
    assume n in dom f;
    then 1 <= n <= len f by FINSEQ_3:25;
    hence thesis by Def6;
  end;
