The Chinese version can be found in the following link URL
https://www.view.sdu.edu.cn/info/1023/138010.htm
The summer lecture “digraph” is designed to provide Shandong University students with top-quality lectures and training to broaden their horizons and stimulate cross-cultural communication. The course was held from July 6 to July 11, 2020, via Zoom online and was given by Professor Jørgen Bang-Jensen from the University of Southern Denmark. It has attracted more than 600 people from more than 70 universities, including undergraduates, postgraduates, Ph.D. students and young scholars. Among the 60 undergraduates or more of Shandong University, the participants come not only from School of Mathematics but also from Taishan School, School of Computer, School of Software, School of Life Sciences, School of Chemistry, etc.
The course started at 14:00 on July 6th. On the course opening ceremony, two professors made a speech: Professor Yubao Guo from Department of Mathematics of Aachen University of Technology (the Vice-President of Adam-Schall Society for German-Chinese Cooperation), and Professor Guanghui Wang, the deputy dean of School of Mathematics and Institute of Data Science of Shandong University. First, as the co-teacher, Professor Jin Yan welcomed participants and introduced Professor Bang-Jensen for his contributions to digraph theory. Professor Guo reviewed the cooperation and friendship with Jørgen, and sent a message to participants to cherish this opportunity taught by Jørgen. Professor Wang appreciated Jørgen teaching the course and hoped the students to enjoy the study for the week.
This course has a total of 32 academic hours. During this period, Professor Bang-Jensen taught the important contents and frontier topics of directed graphs, including network flow and its applications, properties of directed graphs (such as connectivity, Hamiltonian cycles), classes of graphs (tournaments, semi-complete digraphs, locally semi-complete digraphs, quasi-transitive digraphs), characterization of the digraph structure, algorithms and applications, etc. Professor Bang-Jensen proved theorems clearly and logically. He also mentioned anecdotes from related mathematicians, adding a lot of interest to the course. By using slides made by himself in advance and the handwriting board alternately, he taught fluently online. Also, he explained in detail the exercises every night. Despite the heavy workload of preparation and continuous teaching, Professor Bang-Jensen still completed the teaching with full enthusiasm. It is worth point out that Jørgen prepared for the course very well. He communicated with us in dozens of emails to discuss the contents and exercises and modified the plan a few times to take into account learners of various levels.
In the interactive session at the end of the course on July 10, senior professors, young scholars, and students expressed their feelings about the course and their gratitude to Jørgen. Through studying this course, students benefited a lot. They not only mastered the core contents of the directed graphs, stimulated their interest in digraphs, but also broadened their horizons, improved their English ability, and experienced the charm of a mathematician and the essence of mathematics. Some students also wrote cards to Jørgen to express gratitude. After receiving the card, he said: "It makes me very happy".
For the examination, the students handed in their answer papers by sending the electronic files. They wrote extraordinarily neatly and clearly, and some of the answer papers are even in scanned versions, which greatly facilitated the marking. Among the students who took the exam, there are 21 outstanding students. Most of them got the electronic certificate of completion and the outstanding students got the outstanding student certificate and gifts.
To ensure the network connection for so many participants online, our university staff in the information office came to the site to guide and they patiently answered various questions we encountered during the entire course. Also worth mentioning are the course team members- Yun Wang, Jie Zhang, and Suyun Jiang. Their efforts in the course were highly praised by teachers and students. They tested Zoom and communication networks over and over again, made posters, set up QQ groups and WeChat groups. They have recorded videos of the course for the students who cannot attend class on time due to time conflicts. And they often worked until one or two o'clock late at night for video editing, transcribing, uploading. To let the undergraduates know the basic knowledge of digraphs before the lecture, Yun gave the pre-lecture for some basic concepts and properties of digraphs. Jie and Suyun designed a study plan for the undergraduates. During the course, they corrected the homework of the students meticulously and answered questions patiently.
The organization of the course has been guided by Branch of Graph Theory & Combinatorics of the Chinese Society of Operations Research and Committee of Graph Theory, Combinatorics, and Applications of the Chinese Society of Industrial and Applied Mathematics. Academically, this course aims to stimulate interest in digraphs in China, keep abreast of the latest research trends in this field, and focus on important frontier topics.
Author / Jin Yan
Picture / Yun Wang & Jie Zhang