Comment: Synthesis of asymptotically stable linear time-invariant closed-loop systems incorporating multivariable 3-term controllers

The letter contains some elementary observations on a letter in which an inverse Lyapunov technique was propounded as a means for obtaining `gain¿ matrices in such a manner that a linear 3-term controlled closed-loop system was rendered asymptotically stable. While that letter is rigorously correct in most respects, some simple properties of the constituent matrices were overlooked and others were masked by the adoption of the Lyapunov method.