In the talk we present a survey of the current state of art in the area of quadratic functionals with prescribed time derivatives. The ...rst contribution dedicated to the topic was that by Yu.M. Repin [5]. In this seminal contribution a quadratic functional of a general form was suggested. The time derivative of the functional has been computed, and then, equating the derivative to the prescribed one, a system of equations for the matrices that de...ne the functional has been derived. The system includes a linear matrix partial di
Vladimir L. Kharitonov