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arXiv · 2002.05617

Waring rank of binary forms, harmonic cross-ratio and golden ratio

Alexandru Dimca·Gabriel Sticlaru
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Abstract

We discuss the Waring rank of binary forms of degree 4 and 5, without multiple factors, and point out unexpected relations to the harmonic cross-ratio, j-invariants and the golden ratio. These computations of ranks for binary forms are used to show that the combinatorics of a line arrangement in the complex projective plane does not determine the Waring rank of the defining equation even in very simple situations.

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Alexandru Dimca, Gabriel Sticlaru. 2020-02-13. Waring rank of binary forms, harmonic cross-ratio and golden ratio. https://arxiv.org/abs/2002.05617

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