Mixture Proportion Estimation in Weakly Supervised Learning Masashi Sugiyama RIKEN and the University of Tokyo, Japan Abstract Estimation of mixing coefficients in a mixture distribution has a variety of applications in machine learning. For example, under class prior shift, estimation of class priors from labeled training data and unlabeled test data plays an essential role in adaptation; for enabling positive-unlabeled classification, class prior estimation only from positive and unlabeled data is a key challenge; and to cancel the bias caused by label noise, estimation of the noise transition is a central task. In this talk, I will give an overview of our advances in mixture proportion estimation and their use in various machine learning tasks. LQ 2021: 1st International Workshop on Learning to Quantify, Gold Coast, AU, November 1 and November 5, 2021. $ sugi@k.u-tokyo.ac.jp (M. Sugiyama) © 2021 Copyright for this paper by its authors. Use permitted under Creative Commons License Attribution 4.0 International (CC BY 4.0). CEUR Workshop Proceedings http://ceur-ws.org ISSN 1613-0073 CEUR Workshop Proceedings (CEUR-WS.org)