This paper discusses the problem of weakly supervised learning of classification, in which instances are given weak labels that are produced by some label-corruption process. The goal is to derive conditions under which loss functions for weak-label learning are proper and lower-bounded -- two essential requirements for the losses used in class-probability estimation. To this end, we derive a representation theorem for proper losses in supervised learning, which dualizes the Savage representation. We use this theorem to characterize proper weak-label losses and find a condition for them to be lower-bounded. Based on these theoretical findings, we derive a novel regularization scheme called generalized logit squeezing, which makes any proper weak-label loss bounded from below, without losing properness. Furthermore, we experimentally demonstrate the effectiveness of our proposed approach, as compared to improper or unbounded losses. Those results highlight the importance of properness and lower-boundedness. The code is publicly available at https://github.com/yoshum/lower-bounded-proper-losses.

本文讨论了弱监督分类的问题，介绍了一种名为广义逻辑挤压的正则化方案，该方案能使任何合适的弱标签损失函数在下界处有界，而不丢失合理性，并实验验证了该方法的有效性，结果突出了合理性和保下界的重要性。

弱监督分类的下界适当损失