On nonlinear noninteraction with stability

Consideration is given to the problem of rendering a given square affine multi-input multi-output system Σ both noninteractive and stable by means of feedback control. The authors admit feedbacks which involve state augmentation (dynamic feedbacks) and begin by characterizing the class of those feedbacks which achieve resp. maintain noninteraction. They then identify a new distribution associated with Σ which is an invariant for the noninteraction with stability problem. This distribution gives rise to a certain invariant subdynamics of Σ, and the stability of this subdynamics constitutes a necessary condition for the solvability of the problem