English

Code loops in dimension at most 8

Group Theory 2017-12-19 v1

Abstract

Code loops are certain Moufang 22-loops constructed from doubly even binary codes that play an important role in the construction of local subgroups of sporadic groups. More precisely, code loops are central extensions of the group of order 22 by an elementary abelian 22-group VV in the variety of loops such that their squaring map, commutator map and associator map are related by combinatorial polarization and the associator map is a trilinear alternating form. Using existing classifications of trilinear alternating forms over the field of 22 elements, we enumerate code loops of dimension d=dim(V)8d=\mathrm{dim}(V)\le 8 (equivalently, of order 2d+15122^{d+1}\le 512) up to isomorphism. There are 767767 code loops of order 128128, and 8082680826 of order 256256, and 937791557937791557 of order 512512.

Keywords

Cite

@article{arxiv.1712.06524,
  title  = {Code loops in dimension at most 8},
  author = {E. A. O'Brien and Petr Vojtěchovský},
  journal= {arXiv preprint arXiv:1712.06524},
  year   = {2017}
}
R2 v1 2026-06-22T23:21:53.829Z