Yang Wu-chih

Yang Wuzhi, a native of Fengyang, Anhui, was born on April 14, 1896, in Hefei, Anhui Province (now part of Feixi County). His father, Yang Bangsheng, was a late Qing dynasty xiucai who taught at a private school in his early years; in 1905 his mother died, and the family was largely cared for by his uncles. In 1914 he graduated from Anhui Provincial No. 2 High School, and in the same year entered the preparatory department of Beijing Higher Normal School, studying in the Mathematics Department as an undergraduate. He graduated in 1918, and from 1918 to 1922 taught at Anhui Provincial No. 2 High School and Anqing Middle School. In 1922 his eldest son Yang Zhenning (Chen-Ning Yang) was born. In 1923 he went abroad on a government scholarship, first completing his undergraduate studies at Stanford University, and in 1914 transferred to the University of Chicago to study under L. E. Dickson. In 1926 he earned his Master of Science, and in 1928 his PhD; his doctoral thesis was “A Study of the Waring Problem for Pyramidal Numbers” with coefficient representations.

Career: From 1928 to 1929 he taught at Xiamen University, and the following year joined Tsinghua University as a professor in the Mathematics Department. From 1937 to 1946 he taught at the Southwestern Associated University, and from 1946 to 1949 he returned to Tsinghua. From 1950 to 1952 he taught at Tongji University, and from 1950 to 1973 at Fudan University. In the 1950s he taught several courses at Fudan; later, due to diabetes, he remained at home to recuperate. In his later years he lived in Shanghai, with interests in traditional culture and the game of Go (Weiqi).

Family and children: Yang Wuzhi married his fellow townsman Luo Menghua in 1919, and they had their eldest son Yang Zhenning, born in 1922. In 1957, Yang Zhenning was awarded the Nobel Prize in Physics; his father met him in Geneva and other places and also met with overseas scholars. On May 12, 1973, Yang Wuzhi passed away in Shanghai.

Academic contributions: Yang Wuzhi’s doctoral thesis concerned the Waring problem for pyramidal numbers and introduced a theorem on representations with coefficients, showing that every positive integer can be represented as the sum of nine pyramidal numbers. His master’s thesis was “The Invariants of Bilinear Forms” (1926); his doctoral thesis was “Various Generalizations of Waring’s Problem” (1928). Other representative papers include “Representation of Positive Integers by Pyramidal Numbers” (1931) and “Quadratic Fields without Euclid’s Algorithm” (1935). His work contributed to the development of modern number theory education and the number theory school in China; during his time at Tsinghua and the Southwestern Associated University he promoted the teaching and the academic atmosphere of number theory.