G-invariant quadratic forms.
Graded blocks of group algebras with dihedral defect groups
We investigate gradings on tame blocks of group algebras whose defect groups are dihedral. For this subfamily of tame blocks we classify gradings up to graded Morita equivalence, we transfer gradings via derived equivalences, and we check the existence, positivity and tightness of gradings. We classify gradings by computing the group of outer automorphisms that fix the isomorphism classes of simple modules.
Group actions on Cartesian powers with applications to represenation theory.
Group Algebras of Finite Representation Type.
Group algebras of polynomial growth.
Group algebras with centrally metabelian unit groups.
Given a field K of characteristic p > 2 and a finite group G, necessary and sufficient conditions for the unit group U(KG) of the group algebra KG to be centrally metabelian are obtained. It is observed that U(KG) is centrally metabelian if and only if KG is Lie centrally metabelian.
Group extensions and automorphism group rings.
Group rings, Hecke orders, quasi-hereditary orders, cellular orders and deformations.
Group Rings of Circle and Unit Groups.
Group Rings of Finite Representation Type.
Group Rings of Hypercyclic Groups.
Group Rings Whose Units Form an FC-Group.
Group Rings Whose Units Form an FC-Group.
Gruppenalgebren über nichtzyklischen p-Gruppen. I. Die Dieder- und die Quasidiedergruppen.
Hecke algebras and characters of parabolic type of finite group with -pairs
Homology of origamis with symmetries
Given an origami (square-tiled surface) with automorphism group , we compute the decomposition of the first homology group of into isotypic -submodules. Through the action of the affine group of on the homology group, we deduce some consequences for the multiplicities of the Lyapunov exponents of the Kontsevich-Zorich cocycle. We also construct and study several families of interesting origamis illustrating our results.
Homotopy-equivalent group representations.
Ideal decompositions and computation of tensor normal forms.
Indecomposable Modules with Cyclic Vertex.
Indecomposable -lattices for a class of metabelian groups