“…These techniques were generalized and applied to the Kepler problem in [20]. First, in §6 of that work, we use the explicit construction of Kähler metrics with U (n)symmetry [12,5,6] to obtain applications of symplectic coordinates and Hessian geometry. Next, these are applied to the A 1 case of Gibbons-Hawking metrics [8] (i.e., the Eguchi-Hanson metrics [7]), as the Kepler metric on the Kepler manifold K 2 , in [20, §7.2].…”