Szukana fraza: [Abstract = "The aim of this paper is to provide a new, direct approach to the classical LQ problem with an infinite time horizon. In our approach, the LQ problem is formulated as a parametric optimization problem of a special type, and then analysed by the methods presented in our earlier papers \(Grabowski, 1990\; 1993\). The results simplify the well\-known theory presented in \(Curtain and Pritchard, 1978, Sec.4.4\; Zabczyk, 1976\)."]