Incomplete Markets with No Hart Points
提出一个几何检验，判断一般均衡不完全市场经济是否存在哈特点（即证券收益矩阵秩下降的点）。条件(H)若成立则存在哈特点，否则不存在。该条件仅取决于商品数量和证券分红，与禀赋和偏好无关。
We provide a geometric test of whether a general equilibrium incomplete markets (GEI) economy has Hart points---points at which the rank of the securities payoff matrix drops. Condition (H) says that, at each nonterminal node, there is an affine set (of appropriate dimension) that intersects all of a well-specified set of convex polyhedra. If the economy has Hart points, then Condition (H) is satisfied; consequently, if condition (H) fails, the economy has no Hart points. The shapes of the convex polyhedra are determined by the number of physical goods and the dividends of the securities, but are independent of the endowments and preferences of the agents. Condition (H) fails, and thus there are no Hart points, in interesting classes of economies with only short-lived securities, including economies obtained by discretizing an economy with a continuum of states and sufficiently diverse payoffs.