论文标题
绝对没有免费的午餐！
Absolutely No Free Lunches!
论文作者
论文摘要
本文与旨在以无限二进制序列学习模式的学习者有关：显示二进制序列的初始段越长，他们要么试图预测下一个位将是0，要么是1是1，或者他们对这些事件发出预测概率。考虑了此问题的几种变体。在每种情况下，都建立了以下形式的不自由午线结果：学习问题是一个非常困难的结果，因为无论采用哪种方法，失败都比成功更为普遍。在选择一种学习方法时，必须面对艰难的选择，因为没有其他方法在其成功范围内主导所有其他方法。在最简单的情况下，将方法失败和成功的情况集的一组情况进行比较是基数的问题（可计数与无数的情况）；在其他情况下，这是拓扑问题（微薄与联合使用）或混合计算 - 居民（有效地相对于有效的共同涉及）。
This paper is concerned with learners who aim to learn patterns in infinite binary sequences: shown longer and longer initial segments of a binary sequence, they either attempt to predict whether the next bit will be a 0 or will be a 1 or they issue forecast probabilities for these events. Several variants of this problem are considered. In each case, a no-free-lunch result of the following form is established: the problem of learning is a formidably difficult one, in that no matter what method is pursued, failure is incomparably more common that success; and difficult choices must be faced in choosing a method of learning, since no approach dominates all others in its range of success. In the simplest case, the comparison of the set of situations in which a method fails and the set of situations in which it succeeds is a matter of cardinality (countable vs. uncountable); in other cases, it is a topological matter (meagre vs. co-meagre) or a hybrid computational-topological matter (effectively meagre vs. effectively co-meagre).
