In recent years there has been an increasing interest in learning Bayesian networks from data. One of the most effective methods for learning such networks is based on the minimum description length (MDL) principle. Previous work has shown that this learning procedure is asymptotically successful: with probability one, it will converge to the target distribution, given a sufficient number of samples. However, the rate of this convergence has been hitherto unknown. In this work we examine the sample complexity of MDL based learning procedures for Bayesian networks. We show that the number of samples needed to learn an epsilon-close approximation (in terms of entropy distance) with confidence delta is O((1/epsilon)^(4/3)log(1/epsilon)log(1/delta)loglog (1/delta)). This means that the sample complexity is a low-order polynomial in the error threshold and sub-linear in the confidence bound. We also discuss how the constants in this term depend on the complexity of the target distribution. Finally, we address questions of asymptotic minimality and propose a method for using the sample complexity results to speed up the learning process.

研究使用最小描述长度（MDL）原则基于样本复杂性学习贝叶斯网络，并提出了使用样本复杂性结果加速学习过程的方法，同时表明了以熵距离为误差阈值的epsilon-close近似所需样本数量是O((1/epsilon)^(4/3)log(1/epsilon)log(1/delta)loglog(1/delta))。

学习贝叶斯网络的样本复杂度