On Criteria for Closedness of an Attainable Set of a Discrete Neutral Control System1

This paper deals with the closedness of the attainable set in the function space W 1 2 × L2 of a linear neutral system with commensurate delays in state and control. Necessary and sufficient algebraic criteria expressed in terms of the system matrices for the closedness are derived.By the additional restriction that the control is a scalar control, another criterion for closedness, based on the transfer matrix, is indicated and used to verify the results