2024/12/22 by Yoshikazu Yamagishi, Yamagishi, Yoshikazu
Computer Science · #37F10 #52B11 #Computational Geometry and Mesh Generation #Digital Image Processing Techniques #Distributed and Parallel Computing Systems #Dynamical Systems (math.DS) #FOS: Mathematics #Metric Geometry (math.MG)
paper · pdf · doi:10.48550/arxiv.2412.16862
openalex publication_date 2024/12/22 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We study the farthest point mapping on (the boundary of) the 4-cube with respect to the intrinsic metric, and its dynamics as a multivalued mapping. It is a piecewise rational map. It is more complicated than the one on the 3-cube, but it is shown that the limit set of the farthest point map on the 4-cube is the union of the diagonals of eight (3-cube) facets, like the farthest point map on the 3-cube whose limit set is the union of the six (square) facets. This is in contrast to the doubly covered simplices and (the boundary of) the regular 4-simplex, where the limit set is a finite set. If the source point is in the interior of a facet, its limit set is also in the facet. The farthest point mapping is closely related to the star unfolding and source unfolding. We give a loose definition of star unfolding of the surface of a 4-dimensional polytope. We also study the intrinsic radius and diameter of the 4-cube. It is expected that the intrinsic radius/diameter ratio of an n-cube is monotonically decreasing in dimension.