应甘肃省数学与统计学基础学科研究中心邀请，云南大学曹春华教授将为我院师生作学术报告。
报告题目：Compleing Three-word codes
报告摘要：In 1989, Restivo proved that every finite prefix-suffix-composed code has a finite completion. Since one-word codes and two-word codes are prefix-suffix-composed codes, they have finite completions. In 1977, Restivo found a 4-word code having no finite completion. This implies that for each n greater than 4, there exists an n-word code having no finite completion. However, whether every three-word code has a finite completion remains an open question in the Theory of Codes. In 1996, Denis formulated a conjecture that the three-word code {a, aba, ba^2bababa^2b} has no finite completion. Contrary to this, we construct a finite completion for this code. Furthermore, we prove that three-word code with the form {a, ab, v} have finite completions. Finally, we present some series of three-word codes with the form {a, aba, u} that have finite completions. These three-word codes include both prefix-suffix-composed and prefix-suffix-indecomposed.
报告时间：2025年5月14日10:00
报告地点：腾讯会议，会议号：193 508 073
邀 请 人：乔虎生教授
届时欢迎广大师生参与交流！
报告人简介
曹春华，云南大学数学与统计学院教授，云南大学青年骨干教师，研究领域是半群代数理论。主持结题国家自然科学项目2项，主持云南省科技厅应用基础面上项目2项，主持云南省教育厅重点项目和一般项目各1项，参与云南省科技厅高端人才引进项目1项，在《Acta Informaitca》《International Journal of Computer Mathematics》等杂志发表科研论文30多篇。主讲的《抽象代数》课程为云南省研究生优质课程。指导全国大学生数学竞赛，2位同学获国家一等奖，1位同学获国家二等奖，5位同学获国家三等奖，30位同学获省级一等奖，100多位同学获省级二、三等奖； 本人获全国首届高校数学微课程教学设计竞赛西南赛区二等奖；指导云南省优秀硕士学位论文1篇。
甘肃省数学与统计学基础学科研究中心
数学与统计学院
2025年5月12日
