Functorial equivalence classes of 2-blocks of tame representation type
Abstract
For any block of a finite group over an algebraically closed field of characteristic $2$ which has dihedral, semidihedral, or generalized quaternion defect groups, we determine explicitly the decomposition of the associated diagonal $p$-permutation functor over an algebraically closed field $\mathbb{F}$ of characteristic $0$ into a direct sum of simple functors. As a consequence we see that two blocks with dihedral, semidihedral, or generalized quaternion defect groups are functorially equivalent over $\mathbb{F}$ if and only if their fusion systems are isomorphic. It is an open question if two blocks (with arbitrary defect groups) that are functorially equivalent over $\mathbb{F}$ must have isomorphic fusion systems. The converse is wrong in general.
Fields of Study & Subjects
Finite Group Theory Research
Homotopy and Cohomology in Algebraic Topology
Geometric and Algebraic Topology
Publication details
- Journal / source
- Tunisian Journal of Mathematics
- Volume
- 8
- Issue
- 4
- Pages
- 705–721
- Publication date
- 10 September 2026
- Language
- EN