Time-Varying Systems

Section 1 provides a theory of reachability, observability, minimal realization and duality for time-varying linear systems, using only the basic language of linear algebra. Section 2 uses category theory to show that time-varying dynamics for adjoint processes in a category $\mathcal{K}$ may be defined as ad joint processes in a suitable new category $\mathcal{K}^{\bf z} $.