Minimal partial realization by descriptor systems

In this paper a generalization of Kalman's partial realization theory is de veloped using partial realizations defined by descriptor systems. The use o f singular system realizations in contrast to regular linear systems enable s us to circumvent certain technical difficulties inherent in the standard approach to partial realizations. An existence and uniqueness result for mi nimal partial descriptor realizations is proven and a simple rank formula f or the McMillan degree is derived. (C) 2001 Elsevier Science Inc. All right s reserved.