Leetsch C. Hsu

Xu Lizhi (; 23 September 1920 – 11 March 2019), better known as Leetsch Charles Hsu, was a Chinese mathematician and educator. He co-founded the Department of Mathematics of Jilin University and founded the Institute of Applied Mathematics and the Journal of Mathematical Research with Applications at the Dalian University of Technology. Together with American mathematician Henry W. Gould, he established the Gould–Hsu Matrix Inversion Formula in 1973.

Early life and education

Hsu was born on 23 September 1920 in Zhangjiagang, Jiangsu, Republic of China. His original name was Xu Quanyong .

Hsu studied at Jiangsu Provincial Luoshe Normal School before the outbreak of the Second Sino-Japanese War. In 1940, he passed the entrance examination for the temporary National Southwestern Associated University formed by Tsinghua and other universities in Kunming, and studied mathematics under Hua Luogeng and Pao-Lu Hsu. Upon graduation in 1945, he was hired by the university as a teaching assistant to Hua.

In 1951, Hsu returned to China and became an associate professor of mathematics at Tsinghua University. He also taught at Beijing Normal University on a part-time basis. In 2009, he was named by the Dalian University of Technology as one of the most important faculty members in the history of the university. Their collaboration resulted in the establishment of the Gould–Hsu Matrix Inversion Formula in 1973, which is important for computing combinatorial identities.

Hsu published over 170 research papers and more than 10 monographs. He advised 20 doctoral students. and won multiple national and international prizes.

Death Hsu died in Beijing on 11 March 2019, at the age of 98.