A Quiver Presentation for Solomon's Descent Algebra

Abstract

The descent algebra $\Sigma(W)$ is a subalgebra of the group algebra $\Q W$ of a finite Coxeter group $W$, which supports a homomorphism with nilpotent kernel and commutative image in the character ring of $W$. Thus $\Sigma(W)$ is a basic algebra, and as such it has a presentation as a quiver with relations. Here we construct $\Sigma(W)$ as a quotient of a subalgebra of the path algebra of the Hasse diagram of the Boolean lattice of all subsets of $S$, the set of simple reflections in $W$. From this construction we obtain some general information about the quiver of $\Sigma(W)$ and an algorithm for the construction of a quiver presentation for the descent algebra $\Sigma(W)$ of any given finite Coxeter group $W$.