Nakayama automorphisms of graded double Ore extensions of Koszul Artin-Schelter regular algebras with nontrivial skew derivations

TL;DR

This paper studies the Nakayama automorphisms of graded double Ore extensions of Koszul Artin-Schelter regular algebras, providing explicit descriptions and constructing a twisted superpotential to understand their structure.

Contribution

It introduces the concept of $ ext{varsigma}$-divergence, constructs minimal free resolutions, and describes Nakayama automorphisms for these extensions, advancing understanding of their homological properties.

Findings

B is shown to be Koszul via minimal free resolution.

A homological invariant called $ ext{varsigma}$-divergence is introduced.

Explicit description of Nakayama automorphism for B is provided.

Abstract

Let $A$ be a Koszul Artin-Schelter regular algebra and $B=A_P[y_1,y_2;\varsigma,\nu]$ be a graded double Ore extension of $A$ where $\varsigma:A\to M_{2\times 2}(A)$ is a graded algebra homomorphism and $\nu:A\to A^{\oplus 2}$ is a degree one $\varsigma$-derivation. We construct a minimal free resolution for the trivial module of $B$, and it implies that $B$ is still Koszul. We introduce a homological invariant called $\varsigma$-divergence of $\nu$, and with its aid, we obtain a precise description of the Nakayama automorphism of $B$. A twisted superpotential $\hat{\omega}$ for $B$ with respect to the Nakayama automorphism is constructed so that $B$ is isomorphic to the derivation quotient algebra of $\hat{\omega}$.