Voevodsky’s friends remember him as constitutionally unable to compromise on the truth — a quality that led him to produce some of the most important mathematics of the 20th century. Vladimir Voevodsky at the Institute for Advanced Study in 2016. In math as in life, Vladimir Voevodsky played by his own rules. Voevodsky, a Russian-born mathematical prodigy, produced a string of daring insights in the 1990s that revolutionized one of the central fields of mathematics and established him at the pinnacle of his profession. His work continues to reverberate today. On Sept. 30, Voevodsky died in Princeton, New Jersey, at...