Sufficient and Necessary Conditions for the Solvability of the State   Feedback Regulation Problem
  In this paper, we discuss the state feedback output regulation problem (SFRP) for infinite-dimensional linear control systems with infinite-dimensional exosystems. Under the polynomial stabilizability assumption, sufficient and necessary conditions are given for the solvability of the SFRP. The solvability of this problem is characterized in terms of the solvability of a pair of linear regulator equations. An application of the solvability of the SFRP for polynomial stable SISO system is given. 
S. Boulite, H. Bouslous, L. Maniar and R. Saij
math.OC