文摘
The main task of the paper is to investigate the question of the recognition of digital polyhedra with a fixed number of facets: given a finite lattice set \(S\subset \mathbb {Z}^d\) and an integer n, does there exist a polyhedron P of \(\mathbb {R}^d\) with n facets and \(P\cap \mathbb {Z}^d=S\)? The problem can be stated in terms of polyhedral separation of the set S and its complementary \(S^c=\mathbb {Z}^d / S\). The difficulty is that the set \(S^c\) is not finite. It makes the classical algorithms intractable for this purpose. This problem is overcome by introducing a partial order “is in the shadow of”. Its minimal lattice elements are called the jewels. The main result of the paper is within the domain of the geometry of numbers: under some assumptions on the lattice set S (if \(S\subset \mathbb {Z}^2\) is not degenerated or if the interior of the convex hull of \(S\subset \mathbb {Z}^d\) contains an integer point), it has only a finite number of lattice jewels. In this case, we provide an algorithm of recognition of a digital polyhedron with n facets which always finishes.