Hilbert-Chow morphism for non commutative Hilbert schemes and moduli spaces of linear representations

Abstract

Let $k$ be a commutative ring and let $R$ be a commutative $k-$algebra. The aim of this paper is to define and discuss some connection morphisms between schemes associated to the representation theory of a (non necessarily commutative) $R-$algebra $A.$ We focus on the scheme $\ran//\GL_n$ of the $n-$dimensional representations of $A,$ on the Hilbert scheme $\Hilb_A^n$ parameterizing the left ideals of codimension $n$ of $A$ and on the affine scheme Spec ${\Gamma }_R^n(A{)}^{ab}$ of the abelianization of the divided powers of order $n$ over $A.$ We give a generalization of the Grothendieck-Deligne norm map from $\Hilb_A^n$ to Spec ${\Gamma }_R^n(A{)}^{ab}$ which specializes to the Hilbert Chow morphism on the geometric points when $A$ is commutative and $k$ is an algebraically closed field. Describing the Hilbert scheme as the base of a principal bundle we shall factor this map through the moduli space $\ran//\GL_n$ giving a nice description of this Hilbert-Chow morphism, and consequently proving that it is projective.

18 pages

References in corpus (1)

• Cohomology of non-commutative Hilbert schemes