“…Control problems in Banach or Hilbert spaces arise naturally in processes described by partial differential equations (see for example [ 1 , 3 , 7 , 8 , 11 , 13 , 15 , 16 , 19 , 22 ] and references therein). Sometimes it is useful to reduce the control problem for partial differential equations to infinite systems of ODEs [ 4 , 5 , 9 , 10 ].…”