On the complements of 3-dimensional convex polyhedra as polynomial images of ℝ3
Abstract
Let be a convex polyhedron of dimension n. Denote
and let
be its closure. We prove that for n = 3 the semialgebraic sets
and
are polynomial images of ℝ3. The former techniques cannot be extended in general to represent the semialgebraic sets
and
as polynomial images of ℝn if n ≥ 4.
Dedicated to Julio Castellanos on the occasion of his 60th birthday