Infinite Dimensional Multipliers and Pontryagin Principles for   Discrete-Time Problems
  The aim of this paper is to provide improvments to Pontryagin principles in infinite-horizon discrete-time framework when the space of states and of space of controls are infinite-dimensional. We use the method of reduction to finite horizon and several functional-analytic lemmas to realize our aim. 
Mohammed Bachir, Joel Blot
math.OC cs.SY math.FA