Rings of invariants of three-dimensional upper-triangular representations of finite groups

Abstract

The work proves that, for finite three-dimensional upper triangular groups over a field of odd characteristic generated by pseudoreflections, maximal unipotent subgroup of which is abelian, the ring of invariants is polynomial if and only if the maximal unipotent subgroup is generated by pseudoreflections or does not contain transvections.

15 pages