id: 03858933 dt: j an: 03858933 au: Nolte, Cornelia ti: Generalized rank conditions for systems in a category. so: Quaest. Math. 6, 211-226 (1983). py: 1983 pu: NISC (National Inquiry Services Centre), Grahamstown; Taylor \& Francis, Abingdon la: EN cc: ut: Discrete-time bilinear systems; categorial framework; duality principle; reachability ci: li: doi:10.1080/16073606.1983.9632301 ab: Discrete-time bilinear systems over an arbitrary commutative ring R with unity are given by the following equations: $$ q(t+1)=Aq(t)+N(q(t))\otimes u(t)+Bu(t),y(t)=Cq(t) $$ with Q,Y and U R- modules and $N: Q\otimes U\to Q$, A: $Q\to Q$, $B: U\to Q$ and $C: Q\to Y$ R-homomorphisms. In the present paper those systems are considered as systems in the category R-Mod. The concepts of reachability and observability are defined and the known rank criteria for reachability of linear resp. bilinear systems are generalized for arbitrary systems in the category R- Mod with a state modul of finite height. Finally, in the categorial framework a general duality principle between reachability and observability of bilinear systems is established. rv: D.Prätzel-Wolters