Tight lower bound of generalization error in ensemble learning

A machine learning method that integrates multiple component predictors into one predictor is referred to as ensemble learning. In this paper, we derive a tight lower bound of the generalization error in ensemble learning based on asymptotic analysis using a mathematical model based on an exponential mixture of probability distributions and the Kullback-Leibler divergence. In addition, we derive the explicit expression of the weight parameter used in the exponential mixture of probability distributions that minimizes the tight lower bound and discuss the property of the derived weight parameter.