Essential products of nonsingular rings

On Factors of Nonsingular Cartesian Products

We classify all factors of the Cartesian product of any two nonsingular type III , 0 < < 1, or II1, Chacon transformations, as well as the centralizer of nite Cartesian products of such transformations. AMS 1991 subject classi cation: 28D99.

On constant products of elements in skew polynomial rings

Let $R$ be a reversible ring which is $alpha$-compatible for an endomorphism $alpha$ of $R$ and $f(X)=a_0+a_1X+cdots+a_nX^n$ be a nonzero skew polynomial in $R[X;alpha]$. It is proved that if there exists a nonzero skew polynomial $g(X)=b_0+b_1X+cdots+b_mX^m$ in $R[X;alpha]$ such that $g(X)f(X)=c$ is a constant in $R$, then $b_0a_0=c$ and there exist nonzero elements $a$ and $r$ in $R$ such tha...

Cohomology over Fiber products of local rings

Article history: Received 26 April 2007 Communicated by Michel Van Den Bergh

Infinite Products of Zero-dimensional Commutative Rings

Duality Theorems for Crossed Products over Rings

In this note we extend duality theorems for crossed products obtained by M. Koppinen and C. Chen from the case of a base field or a Dedekind domain to the case of an arbitrary noetherian commutative ground ring under fairly weak conditions. In particular we extend an improved version of the celebrated Blattner-Montgomery duality theorem to the case of arbitrary noetherian ground rings.