On Viable Diffusion Price Processes of the Market Portfolio
研究市场组合价格遵循扩散过程的可行性，发现只有特定类型的扩散过程能在简单均衡框架下内生为市场组合价格，并给出了可行性的充要条件。
The assumption that the market portfolio follows a specified diffusion process implies, in a simple equilibrium framework, that the representative individual must have a certain utility function which is identified in the paper. Not every diffusion process is viable, i.e., can be “endogenized” to be the market portfolio's price process in such an equilibrium model. The paper provides necessary and sufficient conditions for viability which imply that viable diffusion processes constitute a rather restricted family.