Lu Jiaxi (; June 10, 1935 – October 31, 1983) was a self-taught Chinese mathematician who made important contributions in combinatorial design theory. He was a high school physics teacher in a remote city and worked in his spare time on the problem of large sets of disjoint Steiner triple systems. Biography Background Lu Jiaxi was born in a poor family in Shanghai. His father was a seller of soy sauce concentrate. His parents had four children, but the three older children all died early from illness, and Lu Jiaxi was the only surviving child. When he was in junior middle school, his father died from an illness that the family could not afford to treat, so he started working after finishing junior middle school in 1949 to earn a living. He served an apprenticeship at an automobile hardware firm in Shanghai. In October 1951, he was admitted to a statistics training course in Shenyang offered by the administration for electrical equipment industry of Northeast China, and he finished first in his class. He was then assigned to a motor factory in Harbin. While working at the factory, he self-studied high school materials. He also learned Russian at a night school, and later English and Japanese to be able to look up literature. In 1956, he joined the fight against the flooding of Songhua River, for which he was commended. In 1957, he passed the college entrance exam and was admitted to Department of Physics of Jilin Normal University, now called Northeast Normal University (not the university that took the same name in 2002). After graduation in 1961, he was assigned to Baotou Steel and Iron Institute, now called Inner Mongolia University of Science and Technology, as a teaching assistant. In 1962, after reorganization of the institute, he was assigned first to the Teaching and Research Office of Baotou Education Bureau, then to several middle schools in Baotou as a physics teacher. He worked at Baotou Eighth Middle School, Baotou Fifth Middle School, Baotou Twenty-fourth Middle School from 1965 to 1973, and Baotou Ninth Middle School from 1973 to his death in 1983. Because of his physics background and his past experience as a factory worker, he was also in charge of a school-run factory which produced radio components. He married in the summer of 1972 to a doctor introduced by his colleague. Mathematical research In the summer of 1956,