报 告 人：林志聪 教授
报告题目：Bijections in weakly increasing trees via binary trees
报告时间：2024年12月14日（周六）上午9：00
报告地点：静远楼1506学术报告厅
主办单位：数学与统计学院、数学研究院、科学技术研究院
报告人简介：
林志聪，山东大学数学与交叉科学研究中心教授，国家优青获得者。主要从事计数组合学的研究，在《J. Combin. Theory Ser. A》、《Combinatorica》、《European J. Combin.》、《Proc. Amer. Math. Soc.》等权威期刊发表SCI学术论文50余篇。任中国数学会计算机数学专业委员会委员和中国运筹学会图论组合分会青年理事。近期的研究兴趣主要集中在排列统计量及其相关组合结构上的双射和同分布问题。
报告摘要：
As a unification of increasing trees and plane trees, the weakly increasing trees labeled by a multiset was introduced by Lin-Ma-Ma-Zhou in 2021. Motived by some symmetries in plane trees proved recently by Dong, Du, Ji and Zhang, we construct four bijections on weakly increasing trees in the same flavor via switching the role of left child and right child of some specified nodes in their corresponding binary trees. Consequently, bijective proofs of the aforementioned symmetries found by Dong et al. and a non-recursive construction of a bijection on plane trees of Deutsch are provided. Applications of some symmetries in weakly increasing trees to permutation patterns and statistics will also be discussed.