 reserve n,i,k,m for Nat;
 reserve p for Prime;
 reserve s, s1, s2 for Real_Sequence;

theorem
  for n being Nat holds Basel-seq.n >= 0
  proof
    let n be Nat;
    Basel-seq.n = 1 / (n ^2) by BASEL_1:31;
    hence thesis;
  end;
