In this example, we consider a proper rational function
in expanded form with ill-conditioned poles.
The set [R.sub.PS] means the ring of (Hurwitz) stable and proper rational functions
. Then all transfer functions can be expressed by the ratio:
The following notation is used: [R.sub.ps] denotes the ring of Hurwitz-stable and proper rational functions
and [I.sub.n] is the unit matrix of dimension n.