by John Allen PaulosLouis BachelierElection season has put an increased focus on the stock market, but little attention is ever paid to the Efficient Market Hypothesis (the EMH, for short). As I’ve written in A Mathematician Plays the Stock Market, it is a fundamental and important notion, but it is also a little weird. Its recent formulation derives from the work of Eugene Fama, economist Paul Samuelson, and others in the 1960s. The basic idea, however, dates back more than 100 years when Louis...