Abstract
Let $p$ be an odd prime and let $k$ be an algebraically closed field of characteristic $p$. Also, let $G$ be a $p'$-group. Then by Maschke's theorem we know $kG\cong \prod_{i=1}^{t} \End_k(V_i)$ as $k$-algebras. Suppose that a $p$-group $P\leq \Aut(G)$ stabilizes $\End_k(V_{i_0})$ for some $i_0$. Such a $V_{i_0}$ will be an endo-permutation $kP$-module. Puig showed that the only modules that occur in this way are those whose image is torsion in the Dade group $D(P)$.
If we let $G$ be any finite group and let $b$ be a defect zero block of $kG$, then $kGb\cong\End_k(L)$ for some $L$. If $kGb$ is $P$-stable for some $p$-group $P\leq \Aut(G)$ and $\Br_P(b)\neq 0$, then $L$ will again be an endo-permutation $kP$-module. We show that if $p\geq 5$, then $L$ is torsion in $D(P)$. This result depends on the classification of the finite simple groups.
Original language | American English |
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Journal | Journal of Group Theory |
Volume | 12 |
State | Published - Nov 6 2008 |
Keywords
- finite groups
- modular representation theory
- nilpotent blocks
- sources algebra
Disciplines
- Mathematics
- Algebra