English

Strongly perfect lattices sandwiched between Barnes-Wall lattices

Number Theory 2021-11-15 v1 Combinatorics Representation Theory

Abstract

New series of 22m2^{2m}-dimensional universally strongly perfect lattices ΛI\Lambda_I and ΓJ\Gamma_J are constructed with 2BW2m#ΓJBW2mΛIBW2m#.2BW_{2m} ^{\#} \subseteq \Gamma _J \subseteq BW_{2m} \subseteq \Lambda _I \subseteq BW _{2m}^{\#} . The lattices are found by restricting the spin representations of the automorphism group of the Barnes-Wall lattice to its subgroup Um:=Cm(41H){\mathcal U}_m:={\mathcal C}_m (4^H_{\bf 1}) . The group Um{\mathcal U}_m is the Clifford-Weil group associated to the Hermitian self-dual codes over F4{\bf F} _4 containing 1{\bf 1}, so the ring of polynomial invariants of Um{\mathcal U}_m is spanned by the genus-mm complete weight enumerators of such codes. This allows us to show that all the Um{\mathcal U}_m invariant lattices are universally strongly perfect. We introduce a new construction, D(cyc)D^{(cyc)} for chains of (extended) cyclic codes to obtain (bounds on) the minimum of the new lattices.

Keywords

Cite

@article{arxiv.1805.01196,
  title  = {Strongly perfect lattices sandwiched between Barnes-Wall lattices},
  author = {Sihuang Hu and Gabriele Nebe},
  journal= {arXiv preprint arXiv:1805.01196},
  year   = {2021}
}