Author's reply

H. Kwakernaak, R. Sivan
1972 IEEE Transactions on Automatic Control  
The authors of the paper under discussion have for a long time realized that there is a connection between their results and the theory of inverse systems. They were not aware of the existence of published results concerning stable inverse systems, however, and, therefore, are grateful to Dr. Godbole for pointing out his references [5] and 161. Corollary 5 of [6] straightforwardly leads to the condition for asympotically vanishing regulation error as given in the paper under discussion for the
more » ... discussion for the case dim ( 2 ) = dim (u). Moreover, [6] gives necessary and s a c i e n t conditions for the case dim (u) > dim (z),
doi:10.1109/tac.1972.1100028 fatcat:47ks6qvt7vf75c6vs5r3mh7y5m