•Let
be rcf and lcf, respectively. Then the following conditions are
equivalent:
1. The feedback system is
internally stable.
2. is invertible in RH¥ 3. is invertible in RH¥
4. is invertible in RH¥ 5. is invertible in RH¥
•Let be a stabilizable and
detectable realization, and let F and L be such that A+BF and A+LC are both stable.
Define
Then
5.