We show that the BRST charge for the N=2 superstring system can be written as Q = e −R (dz 2πi bγ + γ −)e R , where b and γ ± are super-reparametrizations ghosts. This provides a trivial proof of the nilpotence of this operator.

The global structure of the unbounded derived category of a truncated polynomial ring on countably many generators is investigated, via its Bousfield lattice. The Bousfield lattice is shown to have cardinality larger than that of the real numbers, and objects with large tensor-nilpotence height are constructed.

The main result of the work “The nilpotence conjecture in K-theory of toric varieties” is extended to all coefficient fields of characteristic 0, thus covering the class of genuine toric varieties. 1. The statement Let R be a (commutative) regular ring, M be arbitrary commutative, cancellative, torsion free monoid without nontrivial units, and i be a nonnegative integral number. The nilpotence ...

Given an object in a category, we study its orbit algebra with respect to an endofunctor. We show that if the object is periodic, then its orbit algebra modulo nilpotence is a polynomial ring in one variable. This specializes to a result on Ext-algebras of periodic modules over Gorenstein algebras. We also obtain a criterion for an algebra to be of wild representation

In this paper we prove the existence of global nilpotence and global torsion bounds for the cohomology of any finite Hopf subalgebra of the Steenrod algebra for the prime 2. An explicit formula for computing such bounds is then obtained. This is used to compute bounds for H* (sán ) fer n < 6 .

We give a basis for the Hochschild cohomology ring of tame Hecke algebras. We then show that the Hochschild cohomology ring modulo nilpotence is a finitely generated algebra of Krull dimension 2, and describe the support varieties of modules for these algebras.