reserve X for set;
reserve a,b,c,k,m,n for Nat;
reserve i,j for Integer;
reserve r,s for Real;
reserve p,p1,p2,p3 for Prime;
reserve z for Complex;

theorem
  1/2 = 1/2^2 + 1/3^2 + 1/4^2 + 1/6^2 + 1/7^2 + 1/9^2 + 1/12^2 + 1/14^2 +
        1/21^2 + 1/36^2 + 1/45^2 + 1/60^2;
