Serge R. Lang *51

Serge Lang, a leading mathematical theorist and gadfly, died Sept. 12, 2005, in Berkeley, Calif., apparently from heart disease. He was 78.

Born in Paris, Lang moved to California as a teenager, and earned an undergraduate degree from Cal Tech and a Ph.D. from Princeton in mathematics. As a professor at Columbia until 1971 and at Yale until his retirement in 2004, Lang focused on number theory and algebraic geometry, writing more than 40 textbooks and monographs and over 100 articles. He won the prestigious Frank Nelson Cole Prize for outstanding research. In addition, he was a gifted, challenging teacher.

Self-described as a "congenital troublemaker," Lang also circulated large files of letters, essays, news articles, and congressional testimony challenging unscrupulous and sloppy thinking. He criticized the misuse of mathematical equations in economics and other social sciences to give "the illusion of science without any of its substance." He also attacked the suppression of dissident ideas by the scientific establishment. Notably, in the mid-1990s, he argued that the scientific evidence that HIV causes AIDS was faulty.

Lang was elected to the National Academy of Sciences in 1985. In 1998, he published Challenges, a collection of his non-mathematical works.