Comments on "RST Flip-Flop Input Equations"

In a recent paper Graham and Distler¹have shown how all the possible combinations of the input equations of an RST flip-flop can be displayed simultaneously on the Karnaugh maps. This claim is valid only if a1, a2on the R map and a3, a4on the S map are replaced by ai, and each aican be chosen independently of the others. Whereas, in the Graham and Distler techniques, a1chosen to be 1 (or 0) on one vertex of the Karnaugh map implies that all a1are to be 1 (or 0), and the same is true about a2, a3, and a4.