On Mayfield's stability proof for the discretized transparent boundary condition for the parabolic equation

Mayfield's numerical implementation of transparent boundary condition for the Schrödinger-type parabolic equations is revisited. An inaccuracy in the original proof of the conditional stability for the resulting scheme is pointed out. The highly unusual and impressive original result is reestablished and a new proof is presented. Some further remarks and estimates on the instability which occurs when the Mayfield condition is violated are given.