Nonrealizable Planar and Spherical Occlusion Diagrams
摘要
Spherical occlusion diagrams (SOD) were introduced by Viglietta as an axiomatic framework to analyze the visibility maps of points in the interior of a nonconvex polyhedron from which no vertex is visible; and conjectured that every SOD is realizable as a visibility map of a point in some polyhedron. In this paper, we disprove this conjecture, and construct an SOD that is not realizable as a visibility map.