A Counter Example of Invariant Deformation Quantization

In this note, we will show one example of hamiltonian Lie algebra action which has no invariant star product.Comment: 8page

Gelfand-Fuchs cohomology of invariant formal vector fields

Let $\Gamma$ be a finite group acting linearly on a vector space $V$. We compute the Lie algebra cohomology of the Lie algebra of $\Gamma$-invariant formal vector fields on $V$. We use this computation to define characteristic classes for foliations on orbifolds.Comment: 20 page

Hochschild (co)homology of the Dunkl operator quantization of Z2\Z_2-singularity

We study Hochschild (co)homology groups of the Dunkl operator quantization of $\Z_2$-singularity constructed by Halbout and Tang. Further, we study traces on this algebra and prove a local algebraic index formula.Comment: 26 pages. Comments and suggestions welcome. Some typos and other minor mistakes correcte