Kronecker quiver
= Kronecker quiver
{c}
{title2=$K_2$}
The Kronecker quiver has two vertices and two parallel arrows from the first to the second. For a representation with arrows $I,N$, an <endomorphism> consists of the same matrix at both vertices and must commute with $N$. If $N$ is a single <Nilpotent Jordan block>, this centralizer is $k[N]$, yielding an indecomposable non-brick when the block size exceeds one.