 reserve n,i,k,m for Nat;
 reserve p for Prime;

theorem Harm0:
  Harmonic 0 = 0
  proof
    Harmonic 0 = invNAT.0 by SERIES_1:def 1
       .= 1 / 0 by MOEBIUS2:def 2
       .= 0;
    hence thesis;
  end;
