3 papers
math.NT2016
The orthogonal character table of SL2(q)
Oliver Braun, Gabriele Nebe
The rational invariants of the SL_2(q)-invariant quadratic forms on the real irreducible representations are determined. There is still one open question (see Remark 6.5) if q is a…
math.NT2014
Computing in arithmetic groups with Voronoi's algorithm
Oliver Braun, Renaud Coulangeon, Gabriele Nebe +1
We describe an algorithm, meant to be very general, to compute a presentation of the group of units of an order in a (semi)simple algebra over Q. Our method is based on a generalis…
math.NT2013
Perfect Lattices over Imaginary Quadratic Number Fields
Oliver Braun, Renaud Coulangeon
We present an adaptation of Voronoi theory for imaginary quadratic number fields of class number greater than 1. This includes a characterisation of extreme Hermitian forms which i…