On the Four Block Problem and Simultaneous H∞ and L2 Suboptimization

In this paper we obtain a solution to the four block general distance problem which is suboptimal simultaneously with respect to the L∞ norm and the L2 norm. This generalizes some results of [C. Foias and A. F. Frazho, to appear; V. Kaftal et al., J. Funt. Anal., in press].