Research Institute for Mathematical Sciences

Kiyosi Itô

Kiyosi Itô is one of the pioneers of probability theory, and the originator of Ito Calculus. First published in 1942 in Japanese, this epoch-making theory of stochastic differential equations describes nondeterministic and random evolutions. The so-called Ito formula has found applications in other branches of mathematics as well as in various other fields including, e.g., conformal field theory in physics, stochastic control theory in engineering, population genetics in biology, and most recently, mathematical finance in economics. The citation from the National Academy of Science states:

If one disqualifies the Pythagorean Theorem from contention, it is hard to think of a mathematical result which is better known and more widely applied in the world today than "Ito's Lemma." This result holds the same position in stochastic analysis that Newton's fundamental theorem holds in classical analysis. That is, it is the sine qua non of the subject.

Besides being renowned for his brilliant mathematical achievements during a long and productive career spanning over sixty years, Itô has been a truly inspirational teacher to many mathematicians in Japan and abroad. He has received numerous national and international awards and honors, including the 1987 Wolf Foundation Prize in Mathematics, the 1998 Kyoto Prize in Basic Sciences, and the 2003 Japanese Cultural Merit Prize. In 2006, Itô was awarded the first Carl Friedrich Gauss Prize for Applications of Mathematics