English

Universal polar dual pairs of spherical codes found in $E_8$ and $\Lambda_{24}$

Combinatorics 2026-01-01 v1 Classical Analysis and ODEs

Abstract

We identify universal polar dual pairs of spherical codes CC and DD such that for a large class of potential functions hh the minima of the discrete hh-potential of CC on the sphere occur at the points of DD and vice versa. Moreover, the minimal values of their normalized potentials are equal. These codes arise from the known sharp codes embedded in the even unimodular extremal lattices E8E_8 and Λ24\Lambda_{24} (Leech lattice). This embedding allows us to use the lattices' properties to find new universal polar dual pairs. In the process we extensively utilize the interplay between the binary Golay codes and the Leech lattice. As a byproduct of our analysis, we identify a new universally optimal (in the sense of energy) code in the projective space RP21\mathbb{RP}^{21} with 14081408 points (lines). Furthermore, we extend the Delsarte-Goethals-Seidel definition of derived codes from their seminal 19771977 paper and generalize their Theorem 8.2 to show that if a τ\tau-design is enclosed in kτk\leq \tau parallel hyperplanes, then each of the hyperplane's sub-code is a (τ+1k)(\tau+1-k)-design in the ambient subspace.

Keywords

Cite

@article{arxiv.2512.25037,
  title  = {Universal polar dual pairs of spherical codes found in $E_8$ and $\Lambda_{24}$},
  author = {S. V. Borodachov and P. G. Boyvalenkov and P. D. Dragnev and D. P. Hardin and E. B. Saff and M. M. Stoyanova},
  journal= {arXiv preprint arXiv:2512.25037},
  year   = {2026}
}

Comments

72 pages, 15 figures, 4 Tables