Re-Embeddings of Special Border Basis Schemes

Abstract

Border basis schemes are open subschemes of the Hilbert scheme of $\mu$ points in an affine space $\mathbb{A}^n$. They have easily describable systems of generators of their vanishing ideals for a natural embedding into a large affine space $\mathbb{A}^{\mu\nu}$. Here we bring together several techniques for re-embedding affine schemes into lower dimensional spaces which we developed in the last years. We study their efficacy for some special types of border basis schemes such as MaxDeg border basis schemes, L-shape and simplicial border basis schemes, as well as planar border basis schemes. A particular care is taken to make these re-embeddings efficiently computable and to check when we actually get an isomorphism with $\mathbb{A}^{n\mu}$, i.e., when the border basis scheme is an affine cell.