When do Ten Points Lie on a Quadric Surface?

Fuente: arXiv
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Main Author: Traves, Will
Format: Preprint
Published: 2024
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author Traves, Will
author_facet Traves, Will
contents A solution is provided to the Bruxelles Problem, a geometric decision problem originally posed in 1825, that asks for a synthetic construction to determine when ten points in 3-space lie on a quadric surface, a surface given by the vanishing of a degree-2 polynomial. The solution constructs four new points that are coplanar precisely when the ten original points lie on a quadric surface. The solution uses only lines constructed through two known points, planes constructed through three known points, and intersections of these objects. The tools involved include an extension of the Area Principle to three-dimensional space, bracket polynomials and the Grassmann-Cayley algebra, and von Staudt's results on geometric arithmetic. Many special cases are treated directly, leading to the generic case, where three pairs of the points generate skew lines and the remaining four points are in general position. A key step in the generic case involves finding a nice basis for the quadrics that pass through six of the ten points, which uses insights derived from Macaulay2, a computational algebra package not available in the nineteenth century.
format Preprint
id arxiv_https___arxiv_org_abs_2412_05678
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle When do Ten Points Lie on a Quadric Surface?
Traves, Will
Algebraic Geometry
Commutative Algebra
14J70, 51A20 (Primary) 15N05, 15A75, 51N35
A solution is provided to the Bruxelles Problem, a geometric decision problem originally posed in 1825, that asks for a synthetic construction to determine when ten points in 3-space lie on a quadric surface, a surface given by the vanishing of a degree-2 polynomial. The solution constructs four new points that are coplanar precisely when the ten original points lie on a quadric surface. The solution uses only lines constructed through two known points, planes constructed through three known points, and intersections of these objects. The tools involved include an extension of the Area Principle to three-dimensional space, bracket polynomials and the Grassmann-Cayley algebra, and von Staudt's results on geometric arithmetic. Many special cases are treated directly, leading to the generic case, where three pairs of the points generate skew lines and the remaining four points are in general position. A key step in the generic case involves finding a nice basis for the quadrics that pass through six of the ten points, which uses insights derived from Macaulay2, a computational algebra package not available in the nineteenth century.
title When do Ten Points Lie on a Quadric Surface?
topic Algebraic Geometry
Commutative Algebra
14J70, 51A20 (Primary) 15N05, 15A75, 51N35
url https://arxiv.org/abs/2412.05678