Spanning the State Space with Options
研究当基础证券数量不足以覆盖所有可能状态时，衍生品（如期权）能否创造新的跨越机会，从而改善市场效率。
In the Arrow-Debreu approach to uncertainty it has been recognized that an inadequate number of markets in contingent claims would be a source of inefficiency. Several researchers have studied the allocative inefficiencies resulting from incomplete markets, i.e., when the number of independent securities is less than the number of states and therefore the state-space cannot be “spanned†by those securities. In a situation where the number of primitive assets is inadequate to span the state-space, the new spanning opportunities opened up by derived assets written on the primitives is an interesting question.