Equilibrium in CAPM without a Riskless Asset
研究无风险资产时均值-方差CAPM的均衡存在性问题，发现饱和可能导致均衡不存在，且资产价格可能为负或零。通过线性均值-方差效用特例分析，直观解释均衡存在与否的条件。
In the mean-variance CAPM without a riskless asset, the possibility of satiation sometimes leads to non-existence of general equilibrium. Moreover, because portfolio preferences are not necessarily monotone, equilibrium asset prices, when they exist, may be negative or zero. To demonstrate the possibility of non-existence, and to develop an intuitive understanding of when and why equilibrium does or does not exist, this paper fully investigates the special case of utility functions linear in mean and variance and partially extends the results to the general case.