报告题目：Spanning trees with bounded number of leaves and branches报告简介：For a graph $G$, take one vertex $v$ of $G$, and add $k-2$ pendant edges to $v$, and denote the resulting graph by $G'$. Then $G'$ has a spanning $k$-ended tree if and only if $G$ has a hamiltonian path. Hence the problem of determining whether a graph has a spanning $k$-ended tree or not is also NP-complete. Therefore, it is widely believed that it is impossible to find a good necessary and sufficient condition for a graph to have a spanning $k$-ended tree. Thus we mainly deal with sufficient conditions for a graph to have such spanning trees.

报告人：蔡俊青，兰州大学博士学位，主要从事图论及其网络方面的研究，在国际核心期刊《Discrete Mathematics》等发表SCI论文20余篇。主持国家自然科学基金2项、省部级项目2项。2016年到法国巴黎第十一大学进行为期6个月的学术访问，获山东省高等学校科学技术奖三等奖一项。

报告时间：2021年7月24日（星期六）下午 3:00-4:00.

报告地点：腾讯会议，ID：802 979 938

主办单位：扬州大学数学科学学院

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