English

On panel-regular ~A_2 lattices

Group Theory 2017-05-18 v2

Abstract

We study lattices on ~A_2 buildings that preserve types, act regularly on each type of edge, and whose vertex stabilizers are cyclic. We show that several of their properties, such as their automorphism group and isomorphism class, can be determined from purely combinatorial data. As a consequence we can show that the number of such lattices (up to isomorphism) grows super-exponentially with the thickness parameter q. We look in more detail at the 3295 lattices with q in {2,3,4,5}. We show that with one exception for each q these are all exotic. For the exotic examples we prove that the automorphism group of the lattice and of the building coincide, and that two lattices are quasi-isometric only if they are isomorphic.

Keywords

Cite

@article{arxiv.1608.07141,
  title  = {On panel-regular ~A_2 lattices},
  author = {Stefan Witzel},
  journal= {arXiv preprint arXiv:1608.07141},
  year   = {2017}
}

Comments

62 pages, 8 tables, 4 figures, v2 has appendix removed and abelianizations for q=5 corrected

R2 v1 2026-06-22T15:30:43.354Z