A universal deformation formula for $\mathcal{H}_1$ without projectivity assumption

Abstract

We find a universal deformation formula for Connes-Moscovici's Hopf algebra H 1 without any projectivity assumption using Fedosov's quantization of symplectic diffeomorphisms.

Moyal and Rankin-Cohen deformations of algebras

“…TheД described also its action [4] on the algebra of modАlar forms from Вhich a deformation of the latter is obtained. More-oБer the Rankin-Cohen deformation generaliЕes to a АniБersal deformation formАla of H 1 as shoВn bД Tang and Yao [11]. These resАlts are reБieВed in [9].…”

A survey of Rankin-Cohen deformations

“…As a side remark, we also obtained [28] a proof of the associativity of the Eholzer product of a reasonable length using some elementary methods.…”