On testing stability of 2-D discrete systems by a finite collection of 1-D stability tests

A recent paper in these transactions showed that the testing of a two-dimensional (2-D) system can be carried out by a finite collection of suitable 1-D stability tests and presented a stability test for 2-D discrete-time linear system of unprecedented low computational complexity. The new solution was obtained by simplifying an immittance-type tabular 2-D stability test by telepolation (telescoping by interpolation the last polynomial of the 2-D table). This brief presents a similar simplification for another, related but different, immittance-type tabular test. The resulting new procedure is shown to have various aesthetical and practical advantages over the previous form of the solution.