Teiji Takagi

Who was Teiji Takagi?

Teiji Takagi was a Japanese mathematician, best known for proving the Takagi existence theorem in class field theory. The Blancmange curve, the graph of a nowhere-differentiable but uniformly continuous function, is also called the Takagi curve after his work on it.

He was born in the mountainous and rural area of the Gifu Prefecture, Japan. He began learning mathematics in middle school, reading texts in English since none were available in Japanese. After attending a high school for gifted students, he went on to the University of Tokyo, at that time the only university in Japan. There he learned mathematics from such European classic texts as Salmon's Algebra and Weber's Lehrbuch der Algebra. Aided by Hilbert, he then studied at Göttingen. Aside from his work in algebraic number theory he wrote a great number of Japanese textbooks on mathematics and geometry.

He was also instrumental during World War II in the development of Japanese encryption systems; see Purple.