基于在塑造星的集合的空间和连续确实同类的真实值的功能的空间之间的同晶型,塑造星方向性地可辨的功能微分被定义。公式为塑造星 pointwise 最大值和方向性地可辨的功能的一个有限数字的 pointwise 最小微分,并且一二方向性地可辨的功能合成被导出。而且,为方向性地可辨的功能的吝啬值的定理被表明。
Based on the isomorphism between the space of star-shaped sets and the space of continuous positively homogeneous real-valued functions, the star-shaped differential of a directionally differentiable function is defined. Formulas for star-shaped differential of a pointwise maximum and a pointwise minimum of a finite number of directionally differentiable functions, and a composite of two directionaUy differentiable functions are derived. Furthermore, the mean-value theorem for a directionaUy differentiable function is demonstrated.