In the following book,
Model Predictive Control ToolboxTM (User's Guide) Alberto Bemporad Manfred Morari N. Lawrence Ricker
At page 1-6, it has been mentioned that
If the plant is open-loop unstable, the maximum possible p is the number of control intervals required for the plant’s open-loop step response to become infinite.
p means the prediction horizon.
This claim does not look reasonable to me. I have not understood the reason for this claim. What will happen if I choose the prediction horizon longer?