Comments on “Analytical expression of explicit MPC solution via lattice piecewise-affine function” [Automatica 45 (2009) 910–917]

The simplification conditions for lattice representation of the PWA control law in the explicit MPC suggested in the aforementioned article are shown, by means of a counterexample, not to be sufficient. In view of this, a modified lemma is proposed in this note for ensuring the sufficiency.