This paper is devoted to giving simpler proofs of the two fundamental theorems of asset pricing theory, in discrete-time and finite horizon: namely the no-arbitrage theorem, and the market completeness theorem. Some elementary but apparently new results are also given on discrete-time martingale...

Democrats in the US say that taxes can be used to "grease the wheels" of the economy and create wealth enough to recover taxes and thereby increase employment; the Republicans say that taxation discourages investment and so increases unemployment. These arguments cannot both be correct, but both...