A Note on the Dimensions of the Structural Invariant Subspaces of the   Discrete-Time Singular Hamiltonian Systems
  The structural invariant subspaces of the discrete-time singular Hamiltonian system are used in 1] to give an analytic nonrecursive expression of all the admissible trajectories. A deeper insight into the features of these subspaces, particularly focused on the dimensionality issue, is the object of this note. 
Giovanni Marro
cs.SY