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

Abstract

Let $A$ be a Koszul Artin-Schelter regular algebra and $B=A_P[y_1,y_2;ς,ν]$ be a graded double Ore extension of $A$ where $ς:A\to M_{2\times 2}(A)$ is a graded algebra homomorphism and $ν:A\to A^{\oplus 2}$ is a degree one $ς$-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 $ς$-divergence of $ν$, and with its aid, we obtain a precise description of the Nakayama automorphism of $B$. A twisted superpotential $\hatω$ for $B$ with respect to the Nakayama automorphism is constructed so that $B$ is isomorphic to the derivation quotient algebra of $\hatω$.