Higher Koszul brackets on the cotangent complex

Fuente: arXiv
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Main Authors: Herbig, Hans-Christian, Herden, Daniel, Seaton, Christopher
Format: Preprint
Published: 2021
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author Herbig, Hans-Christian
Herden, Daniel
Seaton, Christopher
author_facet Herbig, Hans-Christian
Herden, Daniel
Seaton, Christopher
contents Let $n\ge 1$ and $A$ be a commutative algebra of the form $\boldsymbol k[x_1,x_2,\dots, x_n]/I$ where $\boldsymbol k$ is a field of characteristic $0$ and $I\subseteq \boldsymbol k[x_1,x_2,\dots, x_n]$ is an ideal. Assume that there is a Poisson bracket $\{\:,\:\}$ on $S$ such that $\{I,S\}\subseteq I$ and let us denote the induced bracket on $A$ by $\{\:,\:\}$ as well. It is well-known that $[\mathrm d x_i,\mathrm d x_j]:=\mathrm d\{x_i,x_j\}$ defines a Lie bracket on the $A$-module $Ω_{A|\boldsymbol k}$ of Kähler differentials making $(A,Ω_{A|\boldsymbol k})$ a Lie-Rinehart pair. Recall that $A$ is regular if and only if $Ω_{A|\boldsymbol k}$ is projective as an $A$-module. If $A$ is not regular, the cotangent complex $\mathbb L_{A|\boldsymbol k}$ may serve as a replacement for the $A$-module $Ω_{A|\boldsymbol k}$. We prove that there is a structure of an $L_\infty$-algebroid on $\mathbb L_{A|\boldsymbol k}$, compatible with the Lie-Rinehart pair $(A,Ω_{A|\boldsymbol k})$. The $L_\infty$-algebroid on $\mathbb L_{A|\boldsymbol k}$ actually comes from a $P_\infty$-algebra structure on the resolvent of the morphism $k[x_1,x_2,\dots, x_n]\to A$. We identify examples when this $L_\infty$-algebroid simplifies to a dg Lie algebroid. For aesthetic reasons we concentrate on cases when $ \boldsymbol k[x_1,x_2,\dots, x_n]$ carries a (possibly nonstandard) $\mathbb Z_{\ge 0}$-grading and both $I$ and $\{\:,\:\}$ are homogeneous.
format Preprint
id arxiv_https___arxiv_org_abs_2107_04204
institution arXiv
publishDate 2021
record_format arxiv
spellingShingle Higher Koszul brackets on the cotangent complex
Herbig, Hans-Christian
Herden, Daniel
Seaton, Christopher
Algebraic Geometry
Commutative Algebra
Quantum Algebra
Representation Theory
Symplectic Geometry
17B63 (Primary), 13D02, 58A50, 17B66 (Secondary)
Let $n\ge 1$ and $A$ be a commutative algebra of the form $\boldsymbol k[x_1,x_2,\dots, x_n]/I$ where $\boldsymbol k$ is a field of characteristic $0$ and $I\subseteq \boldsymbol k[x_1,x_2,\dots, x_n]$ is an ideal. Assume that there is a Poisson bracket $\{\:,\:\}$ on $S$ such that $\{I,S\}\subseteq I$ and let us denote the induced bracket on $A$ by $\{\:,\:\}$ as well. It is well-known that $[\mathrm d x_i,\mathrm d x_j]:=\mathrm d\{x_i,x_j\}$ defines a Lie bracket on the $A$-module $Ω_{A|\boldsymbol k}$ of Kähler differentials making $(A,Ω_{A|\boldsymbol k})$ a Lie-Rinehart pair. Recall that $A$ is regular if and only if $Ω_{A|\boldsymbol k}$ is projective as an $A$-module. If $A$ is not regular, the cotangent complex $\mathbb L_{A|\boldsymbol k}$ may serve as a replacement for the $A$-module $Ω_{A|\boldsymbol k}$. We prove that there is a structure of an $L_\infty$-algebroid on $\mathbb L_{A|\boldsymbol k}$, compatible with the Lie-Rinehart pair $(A,Ω_{A|\boldsymbol k})$. The $L_\infty$-algebroid on $\mathbb L_{A|\boldsymbol k}$ actually comes from a $P_\infty$-algebra structure on the resolvent of the morphism $k[x_1,x_2,\dots, x_n]\to A$. We identify examples when this $L_\infty$-algebroid simplifies to a dg Lie algebroid. For aesthetic reasons we concentrate on cases when $ \boldsymbol k[x_1,x_2,\dots, x_n]$ carries a (possibly nonstandard) $\mathbb Z_{\ge 0}$-grading and both $I$ and $\{\:,\:\}$ are homogeneous.
title Higher Koszul brackets on the cotangent complex
topic Algebraic Geometry
Commutative Algebra
Quantum Algebra
Representation Theory
Symplectic Geometry
17B63 (Primary), 13D02, 58A50, 17B66 (Secondary)
url https://arxiv.org/abs/2107.04204