The model-following problem for linear constant (A,B,C,D) quadruples

The aim of this note is to deal with the model-following problem (MFP) for linear constant (
A, B, C, D
) quadruples. In the first part, we tackle the MFP with state feedback, and we extend the results previously given by Morse [7] for (
A, B, C
) triples. The main result of this paper is given in the second part where we give necessary and sufficient conditions under which solutions using (regular) output feedback may exist. Such conditions were lacking up until now.