Concept for function continue function 𝑓 on unbounded(def of bounded) set 𝑆⊆ℝ𝑛 is coercive if lim‖𝑥‖→∞𝑓(𝑥)=+∞ Example 𝑥4−3𝑥3+2𝑥+3 is coercive. but 𝑥3+2𝑥2−𝑥+5 is not coercive.