Bukh's odd-reciprocal conjecture for equiangular lines

Let Nα(n)N_\alpha(n) denote the maximum number of equiangular lines in Rn\mathbb{R}^n with common angle arccosα\arccos\alpha. Bukh's conjecture. If 1/α1/\alpha is an odd natural number, then

Nα(n)=1+α1αn+O(1).N_\alpha(n)=\frac{1+\alpha}{1-\alpha}\,n+O(1).

The paper states that this is the first part of an earlier conjecture and that it was also raised by Bukh. The result proved in the paper covers the relevant range through the spectral-radius-order formula, so the conjecture is consistent with and follows from that theorem.

Sources & referencesView supporting material

Primary source

Zilin Jiang and Alexandr Polyanskii, “Forbidden subgraphs for graphs of bounded spectral radius, with applications to equiangular lines”, arXiv:1708.02317 (2019).

Additional references

2 papers in this index state this conjecture (2016–2017). The statement above is taken from the most recent of them; the others are arXiv:1606.06620.

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