Ehrhart-macdonald Reciprocity Extended
نویسنده
چکیده
For a convex polytope P with rational vertices, we count the number of integer points in integral dilates of P and its interior. The Ehrhart-Macdonald reciprocity law gives an intimate relation between these two counting functions. A similar counting function and reciprocity law exists for the sum of all solid angles at integer points in dilates of P . We derive a unifying generalization of these reciprocity theorems which follows in a natural way from Brion’s Theorem on conic decompositions of polytopes.
منابع مشابه
Tensor valuations on lattice polytopes
The Ehrhart polynomial and the reciprocity theorems by Ehrhart & Macdonald are extended to tensor valuations on lattice polytopes. A complete classification is established of tensor valuations of rank up to eight that are equivariant with respect to the special linear group over the integers and translation covariant. Every such valuation is a linear combination of the Ehrhart tensors which is ...
متن کاملEhrhart theory, modular flow reciprocity, and the Tutte polynomial
Given an oriented graph G, the modular flow polynomial φG(k) counts the number of nowhere-zero Zk-flows of G. We give a description of the modular flow polynomial in terms of (open) Ehrhart polynomials of lattice polytopes. Using Ehrhart–Macdonald reciprocity we give a combinatorial interpretation for the values of φG at negative arguments which answers a question of Beck and Zaslavsky (Adv Mat...
متن کاملA Finite Calculus Approach to Ehrhart Polynomials
A rational polytope is the convex hull of a finite set of points in Rd with rational coordinates. Given a rational polytope P ⊆ Rd, Ehrhart proved that, for t ∈ Z>0, the function #(tP ∩ Zd) agrees with a quasi-polynomial LP(t), called the Ehrhart quasi-polynomial. The Ehrhart quasi-polynomial can be regarded as a discrete version of the volume of a polytope. We use that analogy to derive a new ...
متن کاملun 2 00 3 Counting Lattice Points by means of the Residue Theorem 1
We use the residue theorem to derive an expression for the number of lattice points in a dilated n-dimensional tetrahedron with vertices at lattice points on each coordinate axis and the origin. This expression is known as the Ehrhart polynomial. We show that it is a polynomial in t, where t is the integral dilation parameter. We prove the Ehrhart-Macdonald reciprocity law for these tetrahedra,...
متن کاملq-analogues of Ehrhart polynomials
One considers weighted sums over points of lattice polytopes, where the weight of a point v is the monomial q for some linear form λ. One proposes a q-analogue of the classical theory of Ehrhart series and Ehrhart polynomials, including Ehrhart reciprocity and involving evaluation at the q-integers.
متن کامل