Formality morphism as the mechanism of $\star$-product associativity: how it works

• Datum: 2019
• Автори та афіліації: R. Buring — Johannes Gutenberg University Mainz; A. Kiselev — University of Groningen
• Ключові слова: keywords
• Hauptverfasser: Buring, R., Kiselev, A., Бурінг, Р., Кісєльов, А.
• Format: Artikel
• Sprache: Englisch
• Veröffentlicht: Інститут математики НАН України 2019
• Online Zugang: https://trim.imath.kiev.ua/index.php/trim/article/view/365
• Назва журналу: Transactions of Institute of Mathematics of NAS of Ukraine

The formality morphism $\boldsymbol{\mathcal{F}}=\{{\mathcal{F}}_n$, $n\geqslant1\}$ in Kontsevich's deformation quantization is a collection of maps from tensor powers of the differential graded Lie algebra (dgLa) of multivector fields to the dgLa of polydifferential operators on finite-dimensional affine manifolds. Not a Lie algebra morphism by its term ${\mathcal{F}}_1$ alone, the entire set $\boldsymbol{{\mathcal{F}}}$ is an $L_\infty$-morphism instead. It induces a map of the Maurer-Cartan elements,  taking Poisson bivectors to deformations $\mu_A\mapsto\star_{A[[\hbar]]}$ of the usual multiplication of functions into associative noncommutative $\star$-products of power series in $\hbar$. The associativity of $\star$-products is then realized, in terms of the Kontsevich graphs which encode polydifferential operators, by differential consequences of the Jacobi identity. The aim of this paper is to illustrate the work of this algebraic mechanism for the Kontsevich $\star$-products (in particular, with harmonic propagators).