Further Observations on Blocking Zeros in Linear Muitivariabie systems (RESEARCH NOTE).

While attempting to clarify the confusion concerning the conceptualization of "blocking zeros" in state space in the recent literature, some new observations are made on the relationship between pole-zero cancellation and transmission blocking. An important distinction between uncontrollable and unobservable eigenvalue s is pointed out; and it is argued that the description of a Blocking Zero, at the functional-behavioral level, is not sufficient.