两类资产组合有效前沿边界的相切关系的严格证明

The Strict Proofs of That the Two Kinds of Valid Forward Positions of Asset Portfolios Are Tangent

讨论了资本资产定价模型(CAPM)中两类资产组合有效前沿边界的相切关系,介绍了一些著作和教科书中对它的处理方式,事实上他们均未给出严格意义上的证明.本文对两类资产组合有效前沿边界的相切关系给出了三种较严格的证明.

The tangent relation between the two kinds of valid forward positions of asset portfolios in capital assets pricing model （CAPM） was discussed. And how to deal with it in some literatures was introduced. In fact, a strict proof of it was not given in these literatures. In this paper, three comparatively strict proofs of that the two kinds of valid forward positions of asset portfolios are tangent were given.