English

Poisson brackets symmetry from the pentagon-wheel cocycle in the graph complex

Mathematical Physics 2018-07-17 v1 Combinatorics math.MP Quantum Algebra Symplectic Geometry

Abstract

Kontsevich designed a scheme to generate infinitesimal symmetries P˙=Q(P)\dot{\mathcal{P}} = \mathcal{Q}(\mathcal{P}) of Poisson brackets P\mathcal{P} on all affine manifolds MrM^r; every such deformation is encoded by oriented graphs on n+2n+2 vertices and 2n2n edges. In particular, these symmetries can be obtained by orienting sums of non-oriented graphs γ\gamma on nn vertices and 2n22n-2 edges. The bi-vector flow P˙=Or(γ)(P)\dot{\mathcal{P}} = \text{Or}(\gamma)(\mathcal{P}) preserves the space of Poisson structures if γ\gamma is a cocycle with respect to the vertex-expanding differential in the graph complex. A class of such cocycles γ2+1\boldsymbol{\gamma}_{2\ell+1} is known to exist: marked by N\ell \in \mathbb{N}, each of them contains a (2+1)(2\ell+1)-gon wheel with a nonzero coefficient. At =1\ell=1 the tetrahedron γ3\boldsymbol{\gamma}_3 itself is a cocycle; at =2\ell=2 the Kontsevich--Willwacher pentagon-wheel cocycle γ5\boldsymbol{\gamma}_5 consists of two graphs. We reconstruct the symmetry Q5(P)=Or(γ5)(P)\mathcal{Q}_5(\mathcal{P}) = \text{Or}(\boldsymbol{\gamma}_5)(\mathcal{P}) and verify that Q5\mathcal{Q}_5 is a Poisson cocycle indeed: [ ⁣[P,Q5(P)] ⁣]0[\![\mathcal{P},\mathcal{Q}_5(\mathcal{P})]\!]\doteq 0 via [ ⁣[P,P] ⁣]=0[\![\mathcal{P},\mathcal{P}]\!]=0.

Keywords

Cite

@article{arxiv.1712.05259,
  title  = {Poisson brackets symmetry from the pentagon-wheel cocycle in the graph complex},
  author = {Ricardo Buring and Arthemy V. Kiselev and Nina J. Rutten},
  journal= {arXiv preprint arXiv:1712.05259},
  year   = {2018}
}

Comments

Int. workshop "Supersymmetries and quantum symmetries -- SQS'17" (July 31 -- August 5, 2017 at JINR Dubna, Russia), 4+v pages, 2 figures, 1 table