Model matching for linear systems with delays and 2D systems

Model matching problem for linear systems with delays is considered, via a transfer matrix approach. We deal with a general class of neutral delay-differential systems, which is equivalent to 2D systems, from a realizability point of view. The solution of the problem is based on the decomposition of the ring of the causal rational functions (which is not a principal ideal domain) as the intersection of two suitable principal ideal domains.