The two-dimensional Fornasini-Marchesini model [1], [2] is one of the most general state-spice models available. Although conditions for stability for this model are theoretically simple, actual numerical verification is not a trivial exercise. One way to overcome this problem is to compute the matrix norm

for real

, and the system is stable if this value is less than unity. We compute this value by transforming the two-dimensional system into a canonical form based on the generalized eigenstructure of the state matrices

and

.