ON A CAUSAL LINEAR OPTIMIZATION THEOREM

In this note we specialize our results on causal commutant lifting the ory from Foias and Tannenbaum (J. Funct. Anal. 118 (1993), 407-441) an d Foias et al. (Acta. Sci. Math. 57-(1993), 101-123) to operators with a certain structure which appear in control theory. For such operator s, we give an elementary proof of the causal commutant lifting theorem . (C) 1994 Academic Press, Inc.