reserve a,b,k,m,n,s for Nat;
reserve c,c1,c2,c3 for Complex;
reserve i,j,z for Integer;
reserve p for Prime;
reserve x for object;

theorem Th42:
  for s being Nat holds len PrimeNumbersFS(s) = s
  proof
    let s be Nat;
    len PrimeNumbersFS(s) = len (PrimeNumbersS(s) | s) by AFINSQ_1:def 9;
    hence thesis;
  end;
