Gresham's Law or Gresham's Fallacy?
指出格雷欣法则的两种常见形式（劣币驱逐良币及其固定汇率版本）与历史证据矛盾，提出新版本：当使用非平价货币存在固定交易成本时，法则才成立，且面额决定良币命运。
Gresham's law often takes two forms: the rule that bad money drives out good money and a qualified version of that rule that requires a fixed exchange rate between the two monies. Yet history contradicts both of these forms. In fact, the exchange rate has never been fixed, and we doubt it ever could be. We propose a new version of the law that is more feasible and more consistent with the evidence. It requires a fixed transaction cost of using currencies at nonparprices for the rule to apply. Then denomination determines the fate of good money.