Elkies, Noam, Pretorius, Lou M. and Swanepoel, Konrad
(2006)
*Sylvester-Gallai theorems for complex numbers and quaternions.*
Discrete and Computational Geometry, 35 (3).
pp. 361-373.
ISSN 0179-5376

## Abstract

A Sylvester-Gallai (SG) configuration is a finite set S of points such that the line through any two points in S contains a third point of S. According to the Sylvester-Gallai theorem, an SG configuration in real projective space must be collinear. A problem of Serre (1966) asks whether an SG configuration in a complex projective space must be coplanar. This was proved by Kelly (1986) using a deep inequality of Hirzebruch. We give an elementary proof of this result, and then extend it to show that an SG configuration in projective space over the quaternions must be contained in a three-dimensional flat.

Item Type: | Article |
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Official URL: | http://www.springer.com/math/numbers/journal/454 |

Additional Information: | © 2009 Springer |

Divisions: | Mathematics |

Subjects: | Q Science > QA Mathematics |

Sets: | Departments > Mathematics |

Date Deposited: | 09 Oct 2009 09:50 |

Last Modified: | 20 Jan 2020 03:23 |

URI: | http://eprints.lse.ac.uk/id/eprint/25407 |

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