We prove that the ring of differential operators of any semigroup algebra is finitely generated. In contrast, we also show that the graded ring of the order filtration on the ring of differential operators of a semigroup algebra is finitely generated if and only if the semigroup is scored.  2004 Elsevier Inc. All rights reserved.

The Birman-Murakami-Wenzl algebra (BMW algebra) of type Dn is shown to be semisimple and free over Z[δ, l]/(m(1 − δ) − (l − l)) of dimension (2n +1)n!!− (2 +1)n!, where n!! = 1 ·3 · · · (2n−1). The Brauer algebra of type Dn is a homomorphic ring image and is also semisimple and free of the same dimension, but over the ring Z[δ]. A rewrite system for the Brauer algebra is used in upper bounding ...

Let p : E−→B be a principal bundle with fibre and structure group the torus T ∼ = (C *) n over a topological space B. Let X be a nonsingular projective T-toric variety. One has the X-bundle π : E(X)−→B where E(X) = E × T X, π([e, x]) = p(e). This is a Zariski locally trivial fibre bundle in case p : E−→B is algebraic. The purpose of this note is to describe (i) the singular cohomology ring of E...

Let p : E−→B be a principal bundle with fibre and structure group the torus T ∼ = (C *) n over a topological space B. Let X be a nonsingular projective T-toric variety. One has the X-bundle π : E(X)−→B where E(X) = E × T X, π([e, x]) = p(e). This is a Zariski locally trivial fibre bundle in case p : E−→B is algebraic. The purpose of this note is to describe (i) the singular cohomology ring of E...