Jordan pair assignment via state feedback

This note considers the assignment of the eigenstructure of the closed-loop system via state feedback. This assignment is achieved by assigning the Jordan pair of the denominator matrix polynomial of the controllable MIMO system via state feedback. It turns out that for proper assignment one must take into account the almost forgotten infinite eigenstructure of the system, even though they are invariant under constant state feedback. However, the infinite eigenstructure affects the selection of the eigenvectors.