Bernhard Böhmler (who is also on MO) and myself had the following idea: Let $G$ be a finite group and $k$ a field of characteristic $p$ (algebraically closed when it is needed) such that $p$ divides the order of $G$.
Let $A=kG$ be the group algebra of $G$ and $M$ the direct sum of indecomposable all trivial source modules (that are modules which are indecomposable direct summands of modules of the form ${k\!\uparrow}_H^G$ for some $p$-subgroup $H$ of $G$).
One might ask what properties $B:=End_{kG}(M)$ has.
Quesion 1: Is $B$ studied already in the literature?
The simplest case is when $G$ is abelian and then we can also assume that $G$ is an abelian $p$-group. Then any indecomposable direct summand of $M$ is of the form $k(G/H_i)$ for some subgroup $H_i$ of $G$.
Question 2: When $G$ is an (elementary) abelian $p$-Group, is $B$ a Gorenstein ring?
It might also be interesting whether the relations of $B$ have an easy description, since the Hom-spaces can in principle be described purely combinatorially. We can show that $B$ has dominant dimension equal to $2$.
Our question has a positive answer when $G$ is cyclic and then $B$ has Gorenstein dimension $2$. When $G$ is the Klein four group it is also true and $B$ has Gorenstein dimension 3. One can show that the quiver of $B$ is given by doubling the Hasse quiver of the poset of subgroups of $G$ (that is for every arrow in the Hasse quiver we add the opposite arrow).
For non-abelian groups it is not true, the quaternion group gives a counterexample.
