Equivalent characterizations of zeros in multivariable systems

In this paper we present three equivalent characterizations of what can be termed the zeros of a multivariable system. By establishing this equivalence a connection is made between several large bodies of literature on multivariable system problems. In particular, a polynomial which has arisen quite often in recent work on input isolation, decoupling, model matching, etc. is shown to be identical with a numerator polynomial of the Smith McMillan form of a system transfer function matrix. No proofs are presented here but they can be found in a more inclusive paper being submitted for publication [1].