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Localization theorem for homological vector fields

Vera Serganova, Alexander Sherman

TL;DR

We develop a localization theorem for the cohomology $DS_Q\Bbbk[X]$ of a homological odd vector field $Q$ on a smooth affine supervariety $X$, under the assumption that $Q^2$ acts semisimply and that $Q$ vanishes along a smooth subvariety $Y$ with nondegenerate action on the conormal bundle. The main result identifies $DS_Q\Gamma(X,\mathcal{V})$ with $DS_Q\Gamma(Y,\mathcal{V}|_Y)$ for any $\mathfrak{q}$-equivariant vector bundle $\mathcal{V}$, via a local Koszul-type analysis near $Z(Q)$ and a suitable splitting at points of $Z(Q)$; this recovers simplified descriptions such as $DS_Q\Bbbk[X]=\Bbbk[Y]$ in key cases. The localization is then used to compute the odd-quotient groups $\widetilde{G_u}$ for classical and exceptional supergroups (e.g. $GL(m|n)$ and $Q(n)$), to study homogeneous and symmetric spaces, and to relate $DS_u$ to de Rham-type invariants in Appendix computations. Overall, the work provides a powerful, coordinate-free mechanism to reduce $DS_Q$-cohomology problems on supervarieties to tractable subschemes, with broad implications for representation theory of Lie superalgebras and related physical formalisms.

Abstract

We present a general theorem which computes the cohomology of a homological vector field on global sections of vector bundles over smooth affine supervarieties. The hypotheses and results have the clear flavor of a localization theorem.

Localization theorem for homological vector fields

TL;DR

We develop a localization theorem for the cohomology of a homological odd vector field on a smooth affine supervariety , under the assumption that acts semisimply and that vanishes along a smooth subvariety with nondegenerate action on the conormal bundle. The main result identifies with for any -equivariant vector bundle , via a local Koszul-type analysis near and a suitable splitting at points of ; this recovers simplified descriptions such as in key cases. The localization is then used to compute the odd-quotient groups for classical and exceptional supergroups (e.g. and ), to study homogeneous and symmetric spaces, and to relate to de Rham-type invariants in Appendix computations. Overall, the work provides a powerful, coordinate-free mechanism to reduce -cohomology problems on supervarieties to tractable subschemes, with broad implications for representation theory of Lie superalgebras and related physical formalisms.

Abstract

We present a general theorem which computes the cohomology of a homological vector field on global sections of vector bundles over smooth affine supervarieties. The hypotheses and results have the clear flavor of a localization theorem.
Paper Structure (26 sections, 27 theorems, 98 equations)

This paper contains 26 sections, 27 theorems, 98 equations.

Key Result

Lemma 2.1

Suppose that $X=\operatorname{Spec} A$ is a smooth affine supervariety and $\xi_{1},\dots,\xi_{n}\in A_{\overline{1}}$ are global odd coordinates on $X$. Then the derivations $\partial_{\xi_{1}},\dots,\partial_{\xi_n}$ are well-defined, and if we set $A_0=\operatorname{ker}\partial_{\xi_1}\cap\cdots is an isomorphism.

Theorems & Definitions (65)

  • Remark 1.1
  • Lemma 2.1
  • proof
  • Definition 3.1: Duflo-Serganova functor
  • Lemma 3.2
  • Definition 3.3
  • Definition 3.4
  • Definition 3.5
  • Remark 3.6
  • Lemma 3.7
  • ...and 55 more