English

Slopes of Euclidean lattices, tensor product and group actions

Number Theory 2018-11-26 v2

Abstract

We study the behaviour of the minimal slope of Euclidean lattices under tensor product. A general conjecture predicts that μmin(LM)=μmin(L)μmin(M)\mu_{min}(L \otimes M) = \mu_{min}(L)\mu_{min}(M) for all Euclidean lattices LL and MM. We prove that this is the case under the additional assumptions that LL and MM are acted on multiplicity-free by their automorphism group, such that one of them has at most 22 irreducible components.

Keywords

Cite

@article{arxiv.1806.04984,
  title  = {Slopes of Euclidean lattices, tensor product and group actions},
  author = {Renaud Coulangeon and Gabriele Nebe},
  journal= {arXiv preprint arXiv:1806.04984},
  year   = {2018}
}

Comments

Update of a previous version. The main result is now stated for Hermitian bundles over totally real or CM number fields. A few proofs of intermediate results have been simplified