I want to build a question on state space using a given, nilpotent matrix, $A$.
$$q[n+1]=Aq[n]+Bx[n]$$ $$y[n]=Cq[n]+Dx[n]$$
Usually, I am using the canonical form so there is no problem extracting $A,B,C,D$ from the difference equation of the system. Given a nilpotent $A$, How do I choose reasonable $B,C,D$? can I simply go with the canonical form? Is there anything I should be aware of?