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;

theorem Th6:
  {} in NDSS(V,A)
  proof
    {} is TypeSSNominativeData of V,A by RELSET_1:12;
    hence thesis;
  end;
