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.
