Normal polytopes and ellipsoids
Abstract
We show that: (1) unimodular simplices in a lattice 3-polytope cover a neighborhood of the boundary of the polytope if and only if the polytope is very ample, (2) the convex hull of lattice points in every ellipsoid in R3 has a unimodular cover, and (3) for every d at least 5, there are ellipsoids in Rd, such that the convex hulls of the lattice points in these ellipsoids are not even normal. Part (3) answers a question of Bruns, Michalek, and the author.
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