| 摘要: | Let C be a convex set in Rn. For each yϵC, the cone of C at y, denoted by cone(y, C), is the cone {α(x − y): α ⪖ 0 and xϵC}. If K is a cone in Rn, we shall denote by K∗ its dual cone and by F(K) the lattice of faces of K. Then the duality operator of K is the mapping View the MathML source given by View the MathML source. Properties of the duality operator dK of a closed, pointed, full cone K have been studied before. In this paper, we study dK for a general cone K, especially in relation to dcone(y, K), where yϵK. Our main result says that, for any closed cone K in Rn, the duality operator dK is injective (surjective) if and only if the duality operator dcone(y, K) is injective (surjective) for each vector yϵK ∼ [K ∩ (− K)]. In the last part of the paper, we obtain some partial results on the problem of constructing a compact convex set C, which contains the zero vector, such that cone (0, C) is equal to a given cone. |
