PreprintarXiv licencearXiv
Profinite recognition of uniformity
Abstract
Let G be a semisimple Lie group that is not isogenous to the isometry group of real or complex hyperbolic n-space. We show that the rational rank is a profinite invariant for irreducible lattices in G, unless G has type D2n which forms a genuine exception. In particular, profinitely isomorphic lattices in G of type D2n can have differing virtual cohomological dimension. As another corollary, uniformity is a profinite property for irreducible lattices in G outside type D4. Assuming CSP, the existence of triality symmetries gives uniform and non-uniform profinitely isomorphic lattices in type D4.
Related
BibTeX
@misc{kammeyer2026profinite,
title = {{Profinite recognition of uniformity}},
author = {Holger Kammeyer},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.17041},
eprint = {2610.17041},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.17041},
}
RIS
TY - UNPB
TI - Profinite recognition of uniformity
AU - Holger Kammeyer
PY - 2026
DA - 2026/10/12
PB - arXiv
DO - 10.48550/arxiv.2610.17041
UR - https://arxiv.org/abs/2610.17041
AB - Let G be a semisimple Lie group that is not isogenous to the isometry group of real or complex hyperbolic n-space. We show that the rational rank is a profinite invariant for irreducible lattices in G, unless G has type D_2n which forms a genuine exception. In particular, profinitely isomorphic lattices in G of type D_2n can have differing virtual cohomological dimension. As another corollary, uniformity is a profinite property for irreducible lattices in G outside type D_4. Assuming CSP, the existence of triality symmetries gives uniform and non-uniform profinitely isomorphic lattices in type D_4.
ER -