"The collision of thoughts brings the most joy"- Ji Lijun, the Hall Medal Winner

Recently, ICA, Institute of Combinatorics and its Applications, announced its list of medal winners from 2013 to 2015. Ji Lijun, Professor from the School of Mathematical Science of Soochow University, has been honored with the laureate of the Hall Medal of the year 2015 for his outstanding achievements in combinatorial design theory and its applications in information theory.

Professor Ji was sharing his academic insights with his graduate students when  the journalists came to his office – a simple room on the fourth floor of Weige Building in Soochow University. The journalists were impressed by the simplistic decoration of professor Ji's office as well as his elegant, amiable character and low profile.


Live Everyday Down to Earth

"Ji is a leader in the area of combinatorial design theory and its applications in information theory". This is the comment from ICA when Ji was awarded.

Founded in 1990, the ICA is an international scientific organization in combinatorics and its applications. With members from over 40 countries, the ICA awards the Euler Medals, the Hall Medals, and the Kirkman Medals annually, in which the Euler Medals is for recognition of lifetime contribution while Hall Medals and Kirkman Medals recognize outstanding achievements by members who are aged below 40 and who are within four years past their Ph.D. respectively. In 2016, the ICA instituted the ICA medal, also known as the Stanton Medal, in honor of significant lifetime contributions of its members to promote the teaching of the discipline in combinatorics.

The nominators of Ji highlighted his "outstanding contributions", his "good taste in research problems", and his "potential to be one of the thought leaders in [the] design theoretic community".

When the chairman of the ICA sent Professor Ji the notification of his award, Ji kept it quiet until other academics congratulated him on the news; yet Ji continues his life and work with a down-to-earth attitude.

"Mathematic research requires solitude from a simple way of living. Only when a modest lifestyle is accepted, solid research can be conducted." During the whole interview, Ji kept describing himself as a "common and lucky" man. He humbled that he was just living an ordinary life guiding students, reading books, and conduct research every day. "There is nothing extraordinary."


"Mathematical Research is Full of Fun Yet It Might Not Always Pay Off."

The bond between Ji and mathematics begun since his entered college in 1994. Back then, immersed in the simplicity and grace of the Integrity Building of Soochow University, and inspired by the masterminds in mathematical department, Ji decided to stay and its has been 23 years till today.

In theoretical mathematics, many unsolved problems are isolated in theory. Their solution has little direct contribution to daily life but is of significant value for the establishment of methodology in research. Ji is devoted to solving these problems.

In recent years, his research focuses on three-wise balanced designs, Steiner quadruple systems with desired properties, large sets of triple systems, orthogonal arrays, covering arrays, group divisible 3-designs and their applications in optical orthogonal codes, authentication codes, constant weight codes, and frequency hopping sequences. He has been honored the award for mathematical achievement in the 3rd convention in Jiangsu Province, the first outstanding young people grant of National Science Foundation of China, and as the key participant of two major programs of NSFC, he had published 51 articles in international journals.

"Mathematical research requires accumulation because inspiration only comes after a certain degree of accumulation." Professor Ji noted that he enjoys most the moment of enlightenment, the passion and joy can only be given by math. "Mathematical research doesn't always pay off but the joy lies in the collision of thoughts."


To Excel in Thinking as the Spirit of Scientific Research in Honor of Predecessors

The research center of combinatorics in Soochow University is among the leading institutes of this field both domestically and internationally. This has been earned by a group of leading characters in combinatorics, such as Professor Zhu Lie and Professor Yin Jianxing, who have achieved world renowned scientific achievements.

Dated back to 2004, Professor Zhu, the mentor of Professor Ji, received the lifetime award for his contributions by the ICA. Ji's fellow mentees have also won the Hall and Kirkman Medals. According to Ji, he is just following the spirit of his mentor by conducting beneficial exploration and attempts in combinatorics and its applications.

During his postgraduate years, Ji's diligence allowed him to be accepted by his mentor and to start his Ph.D. under Professor Zhu, who had quite strict requirements from each of his students and assigned them with valuable research tasks worldwide with little overlap.

"If you cannot finish your program in three years, then study for four years." This is what Professor Zhu used to say to Ji back then and Ji kept it in mind till now. To finish his assignment, Ji always sat for more than ten hours with his principle "never write anything useless" in mind. "By the second semester of the second year in my Ph.D. study, I finally had some clues about my dissertation. With only one year left before my graduation, you could tell how much pressure I had." After he solved the tasks and received the approval from his mentor, Ji finally finished his dissertation. "I'm lucky to have my mentor around me all the time. He pushed me, which was what encouraged me to move forward," Ji said, with gratitude to his mentor.

Now, Professor Ji has become the pilot of his graduate students in scientific research. He always reminds his students that study and research are two different things and that they need not only the ability to study on their own but also to discover, analyze and solve problems on their own. According to him, "one must follow the great spirit of his teacher and hold their students accountable with diligence, effort, and a whole good heart."