|
Γ-CONVEXITY
Zhouqin Jia, Wenzhi Liu Liping Yuan, Tudor Zamfirescu
数学物理学报(英文版). 2025 (1):
3-15.
DOI: 10.1007/s10473-025-0101-2
Let F be a family of sets in Rd (always d≥2). A set M⊂Rd is called F-convex, if for any pair of distinct points x,y∈M, there is a set F∈F such that x,y∈F and F⊂M. We obtain the Γ-convexity, when F consists of Γ-paths. A Γ-path is the union of both shorter sides of an isosceles right triangle. In this paper we first characterize some Γ-convex sets, bounded or unbounded, including triangles, regular polygons, subsets of balls, right cylinders and cones, unbounded planar closed convex sets, etc. Then, we investigate the Γ-starshaped sets, and provide some conditions for a fan, a spherical sector and a right cylinder to be Γ-starshaped. Finally, we study the Γ-triple-convexity, which is a discrete generalization of Γ-convexity, and provide characterizations for all the 4-point sets, some 5-point sets and Zd to be Γ-triple-convex.
参考文献 |
相关文章 |
计量指标
|