释义 |
Ehrhart PolynomialLet denote an integral convex Polytope of Dimension in a lattice , and let denote the number of Lattice Points in dilated by a factor of the integer ,
 | (1) |
for . Then is a polynomial function in of degree with rational coefficients
 | (2) |
called the Ehrhart polynomial (Ehrhart 1967, Pommersheim 1993). Specific coefficients have important geometricinterpretations.- 1.
is the Content of . - 2.
is half the sum of the Contents of the -D faces of . - 3.
. Let denote the sum of the lattice lengths of the edges of , then the case corresponds toPick's Theorem,
 | (3) |
Let denote the sum of the lattice volumes of the 2-D faces of , then the case gives
 | (4) |
where a rather complicated expression is given by Pommersheim (1993), since can unfortunately not beinterpreted in terms of the edges of . The Ehrhart polynomial of the tetrahedron with vertices at(0, 0, 0), ( , 0, 0), (0, , 0), (0, 0, ) iswhere is a Dedekind Sum, , , (here, gcd is the Greatest Common Divisor), and (Pommersheim 1993).See also Dehn Invariant, Pick's Theorem References
Ehrhart, E. ``Sur une problème de géométrie diophantine linéaire.'' J. Reine angew. Math. 227, 1-29, 1967.MacDonald, I. G. ``The Volume of a Lattice Polyhedron.'' Proc. Camb. Phil. Soc. 59, 719-726, 1963. McMullen, P. ``Valuations and Euler-Type Relations on Certain Classes of Convex Polytopes.'' Proc. London Math. Soc. 35, 113-135, 1977. Pommersheim, J. ``Toric Varieties, Lattices Points, and Dedekind Sums.'' Math. Ann. 295, 1-24, 1993. Reeve, J. E. ``On the Volume of Lattice Polyhedra.'' Proc. London Math. Soc. 7, 378-395, 1957. Reeve, J. E. ``A Further Note on the Volume of Lattice Polyhedra.'' Proc. London Math. Soc. 34, 57-62, 1959. |