Results 161 to 170 of about 1,034,783 (201)

On the Gorenstein cohomological dimension of group extensions

Journal of Algebra, 2022
The Gorenstein cohomological dimension is defined for any group G and coincides with the virtual cohomological dimension vcdG, whenever the latter is defined and finite.
Ioannis Emmanouil, Olympia Talelli
exaly   +1 more source

Cohomological Dimension of Complexes [PDF]

Communications in Algebra, 2004
In the derived category of the category of modules over a commutative Noetherian ring $R$, we define, for an ideal $\fa$ of $R$, two different types of cohomological dimensions of a complex $X$ in a certain subcategory of the derived category, namely $\cd(\fa, X)=\sup\{\cd(\fa, \H_{\ell}(X))-\ell|\ell\in\Bbb Z\}$ and $-\inf{\mathbf R}\G_{\fa}(X ...
Siamak Yassemi, Mohammad Taghi Dibaei
exaly   +3 more sources

Bredon cohomological dimensions for proper actions and Mackey functors

Forum Mathematicum, 2015
For groups with a uniform bound on the length of chains of finite subgroups, we study the relationship between the Bredon cohomological dimension for proper actions and the notions of cohomological dimension one obtains by restricting the coefficients of
Dieter Degrijse
exaly   +2 more sources

Cohomological Dimension of Generalized Local Cohomology Modules

Algebra Colloquium, 2008
The study of the cohomological dimension of algebraic varieties has produced some interesting results and problems in local algebra. Let 𝔞 be an ideal of a commutative Noetherian ring R. For finitely generated R-modules M and N, the concept of cohomological dimension cd 𝔞(M, N) of M and N with respect to 𝔞 is introduced.
Amjadi, Jafar, Naghipour, Reza
openaire   +1 more source

Compactifications and cohomological dimension

Topology and Its Applications, 1993
zbMATH Open Web Interface contents unavailable due to conflicting licenses.
Jerzy Dydak
exaly   +2 more sources

On the Cohomological Dimension of Soluble Groups

Canadian Mathematical Bulletin, 1981
AbstractIt is known that every torsion-free soluble group G of finite Hirsch number hG is countable, and its homological and cohomological dimensions over the integers and rationals satisfy the inequalitiesWe prove that G must be finitely generated if the equality hG = cdQG holds.
Gildenhuys, D., Strebel, R.
openaire   +2 more sources

The Cohomological Dimension of a Directed Set

Canadian Journal of Mathematics, 1973
Let R be a ring with identity, and let C be a small, nonempty category. We denote the category of right R-modules by AbR and the category of contravariant functors C → AbR by AbRC*. The limit functoris left exact, and its kth right derived functor is denoted by colimk.
openaire   +1 more source

Cohomological Dimension of Algebraic Varieties

The Annals of Mathematics, 1968
Let X be a scheme of finite type over a field k. The cohomological dimension of X is the smallest integer n > 0 such that H'(X, F) = 0 for all i > n, and for all quasi-coherent sheaves F on X. There are two well-known theorems about the cohomological dimension of X.
openaire   +2 more sources

A bound for the Bredon cohomological dimension

Journal of Group Theory, 2007
Summary: We prove that if \(G\) is a group with a bound on the lengths of finite subgroups and \(G\) has finite Bredon cohomological dimension, then this dimension is bounded by the sum of the previous bound and the projective dimension of a certain \(\mathbb{Z} G\)-module.
openaire   +1 more source

Periodic cohomology and subgroups with bounded Bredon cohomological dimension

Mathematical Proceedings of the Cambridge Philosophical Society, 2008
AbstractMislin and Talelli showed that a torsion-free group in$\HF$with periodic cohomology after some steps has finite cohomological dimension. In this note we look at similar questions for groups with torsion by considering Bredon cohomology. In particular we show that every elementary amenable group acting freely and properly on some$\R^n$×Smadmits ...
Jo, Jang Hyun, Nucinkis, Brita E.A.
openaire   +2 more sources