On the reconstruction problem for Pascal lines

Abstract

Given a sextuple of distinct points $A,B,C,D,E,F$ on a conic, arranged into an array $\left[\begin{array}{ccccc}A& B& CF& E& D\end{array}\right]$, Pascal's theorem says that the points $AE\cap BF,BD\cap CE,AD\cap CF$ are collinear. The line containing them is called the Pascal of the array, and one gets altogether sixty such lines by permuting the points. In this paper we prove that the initial sextuple can be explicitly reconstructed from four specifically chosen Pascals. The reconstruction formulae are encoded by some transvectant identities which are proved using the graphical calculus for binary forms.

24 pages, 37 figures

Cited by in corpus (1)

• An algebraic independence result related to a conjecture of Dixmier on binary form invariants