reserve a,a1,a2,v,v1,v2,x for object;
reserve V,A for set;
reserve m,n for Nat;
reserve S,S1,S2 for FinSequence;
reserve D,D1,D2 for NonatomicND of V,A;

theorem Th30:
  {} is NonatomicND of V,A
  proof
    take S = <*NDSS(V,A)*>;
    Union S = NDSS(V,A) by FINSEQ_3:135;
    then (the PartFunc of V,A) | {} in Union S;
    hence thesis by Th27;
  end;
