RIP ITO

Kyyoshi Ito may not mean much to many; but if you study stochastic and probability methods, his name rings loudly. He is one of the architects that developed and refined the math used today to describe systems with random characteristics, in fields as diverse as finance and physics.

Ito's Lemma is probably his most famous result: this is the stochastic (ie, random) equivalent of the chain rule in derivative calculus. Without his contribution, the Black-Scholes equations/results would not be possible. Though maybe, given recent events, that would be a good thing.

Anyway, he has recently passed. Stirling Newberry attempts to explain the significance of Ito's work. Here are  more organized explanations of his work and its significance.

Hmmm. Finance professor has almost identical thoughts.