The economists who began using statistics to analyze financial markets in the 1950s have been credited with revolutionizing the scholarship of investing and with inaugurating modern financial economics. By examining the work of economists who used statistics to analyze financial markets before...

A P-sigma-martingale density for a given stochastic process S is a local P-martingale Z0 starting at 1 such that the product ZS is a P-sigma-martingale. Existence of a P-sigma-martingale density is equivalent to a classic absence-of-arbitrage property of S, and it is invariant if we replace the...