Unsupervised Detection of Downward-Entailing Operators By Maximizing Classification Certainty Jackie Chi Kit Cheung author Gerald Penn author 2012-04 text Proceedings of the 13th Conference of the European Chapter of the Association for Computational Linguistics Walter Daelemans editor Association for Computational Linguistics Avignon, France conference publication cheung-penn-2012-unsupervised https://aclanthology.org/E12-1071/ 2012-04 696 705