Auslander's Theorem for permutation actions on noncommutative algebras (1705.00068v2)

Abstract: When $A = \mathbb{k}[x_1, \ldots, x_n]$ and $G$ is a small subgroup of $\operatorname{GL}n(\mathbb{k})$, Auslander's Theorem says that the skew group algebra $A # G$ is isomorphic to $\operatorname{End}{A^G}(A)$ as graded algebras. We prove a generalization of Auslander's Theorem for permutation actions on $(-1)$-skew polynomial rings, $(-1)$-quantum Weyl algebras, three-dimensional Sklyanin algebras, and a certain graded down-up algebra. We also show that certain fixed rings $A^G$ are graded isolated singularities in the sense of Ueyama.