yψ ց m//G a/WV → t /WG where a ⊆ t is a subspace, WV ⊆ GL(a ) is a reflection group, and ψ is faithfully flat with irreducible generic fibers. Note that WV being a reflection group implies that a /WV is isomorphic to an affine space. The group WV is a very subtle invariant of V which plays a similar role as the Weyl group of the restricted root system for a symmetric space. The morphism ψ facto...

We give an explicit formula for sp2n-basic representatives of the cyclic cohomology of the Weyl algebra HC(A2n). This paper can be seen as cyclic addendum to the paper [6] by Feigin, Felder and Shoikhet, where the analogous Hochschild case was treated. As an application, we prove a generalization of a Theorem of Nest and Tsygan concerning the relation of the Todd class and the cyclic cohomology...