reserve a,b,c,k,m,n for Nat;
reserve i,j for Integer;
reserve p for Prime;

theorem
  for x,y,z,t being non zero Integer holds
  x^2 + 6*y^2 <> z^2 or 6*x^2 + y^2 <> t^2
  proof
    let x,y,z,t be non zero Integer;
    |.x.|^2 = x^2 & |.y.|^2 = y^2 & |.z.|^2 = z^2 & |.t.|^2 = t^2
    by COMPLEX1:75;
    hence thesis by Lm24;
  end;
