English

Formality for g-manifolds

Differential Geometry 2019-10-22 v3 Quantum Algebra

Abstract

To any g\mathfrak{g}-manifold MM are associated two dglas tot(ΛgkTpoly)\operatorname{tot}\big(\Lambda^{\bullet} \mathfrak{g}^\vee \otimes_{\Bbbk} T_{\operatorname{poly}}^{\bullet} \big) and tot(ΛgkDpoly)\operatorname{tot} \big(\Lambda^{\bullet} \mathfrak{g}^\vee\otimes_{\Bbbk} D_{\operatorname{poly}}^{\bullet} \big), whose cohomologies HCE(g,Tpoly0Tpoly+1)H_{\operatorname{CE}}(\mathfrak{g}, T_{\operatorname{poly}}^{\bullet} \xrightarrow{0} T_{\operatorname{poly}}^{\bullet+1}) and HCE(g,Dpoly0Dpoly+1)H_{\operatorname{CE}}(\mathfrak{g}, D_{\operatorname{poly}}^{\bullet} \xrightarrow{0} D_{\operatorname{poly}}^{\bullet+1}) are Gerstenhaber algebras. We establish a formality theorem for g\mathfrak{g}-manifolds: there exists an LL_\infty quasi-isomorphism Φ:tot(ΛgkTpoly)tot(ΛgkDpoly)\Phi: \operatorname{tot}\big(\Lambda^{\bullet} \mathfrak{g}^\vee \otimes_{\Bbbk} T_{\operatorname{poly}}^{\bullet} \big) \to \operatorname{tot} \big(\Lambda^{\bullet} \mathfrak{g}^\vee\otimes_{\Bbbk} D_{\operatorname{poly}}^{\bullet} \big) whose first `Taylor coefficient' (1) is equal to the Hochschild-Kostant-Rosenberg map twisted by the square root of the Todd cocycle of the g\mathfrak{g}-manifold MM and (2) induces an isomorphism of Gerstenhaber algebras on the level of cohomology. Consequently, the Hochschild-Kostant-Rosenberg map twisted by the square root of the Todd class of the g\mathfrak{g}-manifold MM is an isomorphism of Gerstenhaber algebras from HCE(g,Tpoly0Tpoly+1)H_{\operatorname{CE}}(\mathfrak{g}, T_{\operatorname{poly}}^{\bullet} \xrightarrow{0} T_{\operatorname{poly}}^{\bullet+1}) to HCE(g,Dpoly0Dpoly+1)H_{\operatorname{CE}}(\mathfrak{g}, D_{\operatorname{poly}}^{\bullet} \xrightarrow{0} D_{\operatorname{poly}}^{\bullet+1}).

Keywords

Cite

@article{arxiv.1701.04872,
  title  = {Formality for g-manifolds},
  author = {Hsuan-Yi Liao and Mathieu Stiénon and Ping Xu},
  journal= {arXiv preprint arXiv:1701.04872},
  year   = {2019}
}

Comments

8 pages. Updated references. Fix typos. To appear in Compte Rendus Math

R2 v1 2026-06-22T17:52:39.829Z