Before revision: Definition Definition : An estimator is called minimax with respect to a risk function if it achieves the smallest maximum risk among all estimators, meaning it satisfies Least favorable distribution Logically, an estimator is minimax when it is the best in the worst case.
After revision: In other words, for each ,Definition Definition : An estimator is called minimax with respect to a risk function if it achieves the smallest maximum risk among all estimators, meaning it satisfies Least favorable distribution Logically, an estimator is minimax when it is the best in the worst case.