ABSTRACT
The fundamentals of the factorization approach will be explained for linear systems with rational transfer functions whose input u and output y are scalar quantities. We suppose that u and y live in a space of functions mapping a time set into a value set. The time set is a subset of real numbers bounded on the left, say R+ (the nonnegative reals) in the case of continuous-time systems and Z+ (the nonnegative integers) for discrete-time systems. The value set is taken to be the set of real numbers R.
