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Related papers: A criterion for cohomological dimension

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In this article, we prove several transfer principles for the cohomological dimension of fields. Given a fixed field $K$ with finite cohomological dimension $\delta$, the two main ones allow to: - construct totally ramified extensions of…

Number Theory · Mathematics 2025-09-10 Diego Izquierdo , Giancarlo Lucchini Arteche

Let $q$ be a non-negative integer. We prove that a perfect field $K$ has cohomological dimension at most $q+1$ if, and only if, for any finite extension $L$ of $K$ and for any homogeneous space $Z$ under a smooth linear connected algebraic…

Algebraic Geometry · Mathematics 2022-06-13 Diego Izquierdo , Giancarlo Lucchini Arteche

Let F be a field of characteristic 2. In this paper we determine the Kato-Milne cohomology of the rational function field F(x) in one variable x. This will be done by proving an analogue of the Milnor exact sequence [4] in the setting of…

Commutative Algebra · Mathematics 2025-03-24 Ahmed Laghribi , Trisha Maiti

We determine the homological dimension of various isogeny categories of commutative algebraic groups over a field $k$, in terms of the cohomological dimension of $k$ at certain primes. This generalizes results of Serre, Oort and Milne, by…

Algebraic Geometry · Mathematics 2018-09-18 Michel Brion

We recall some basic computations in the Milnor-Witt K-theory of a field, following Morel. We then focus on the Witt K-theory of a field of characteristic two and give an elementary proof of the fact that it is isomorphic as a graded ring…

Algebraic Geometry · Mathematics 2023-06-30 Robin Carlier

Let $\mathbb K$ be a field of characteristic zero. We prove that its motivic cohomology in degree $m-1$ and weight $m$ is rationally isomorphic to the cohomology of the polylogarithmic complex. This gives a partial extension of A. Suslin…

Algebraic Geometry · Mathematics 2025-10-21 Vasily Bolbachan

Let R be a commutative Noetherian (not necessarily local) ring with identity and a be a proper ideal of R. We introduce a notion of a-relative system of parameters and characterize them by using the notion of cohomological dimension. Also,…

Commutative Algebra · Mathematics 2019-05-30 Kamran Divaani-Aazar , Akram Ghanbari Doust , Massoud Tousi , Hossein Zakeri

We determine an upper bound for the cohomological dimension of the complement of a closed subset in a projective variety which possesses an appropriate stratification. We apply the result to several particular cases, including the…

Algebraic Geometry · Mathematics 2015-03-24 Mihai Halic , Roshan Tajarod

In this paper, we study dimensions of some varieties, that were introduced recently by Kisin in order to prove modularity of some Galois representations. In fact, we mainly consider a special case for which we obtain an estimation of the…

Number Theory · Mathematics 2011-02-01 Xavier Caruso

Our investigation focuses on an additive analogue of the Bloch-Gabber-Kato theorem which establishes a relation between the Milnor $K$-group of a field of positive characteristic and a Galois cohomology group of the field. Extending the…

K-Theory and Homology · Mathematics 2024-09-04 Toshiro Hiranouchi

The (co)homological dimension of homomorphism $\phi:G\to H$ is the maximal number $k$ such that the induced homomorphism is nonzero for some $H$-module. The following theorems are proven: THEOREM 1. For every homomorphism $\phi:G\to H$ of a…

Algebraic Topology · Mathematics 2023-02-28 Aditya De Saha , Alexander Dranishnikov

It it shown that the Bloch-Kato conjecture on the norm residue homomorphism $K^M(F)/l \to H^*(G_F,Z/l)$ follows from its (partially known) low-degree part under the assumption that the Milnor K-theory algebra $K^M(F)/l$ modulo $l$ is…

alg-geom · Mathematics 2013-10-29 Leonid Positselski , Alexander Vishik

If T is an algebraic torus defined over a discretely valued field K with perfect residue field k, we relate the K-cohomology of T to the k-cohomology of certain objects associated to T. When k has cohomological dimension <= 1, our results…

Number Theory · Mathematics 2013-12-04 Alessandra Bertapelle , Cristian D. Gonzalez-Aviles

On the category of pairs of topological spaces having a homotopy type of $CW$ complexes the singular (co)homology theory was axiomatically studied by J.Milnor. In particular, Milnor gave additivity axiom for a (co)homology theory and proved…

Algebraic Topology · Mathematics 2019-11-14 Anzor Beridze , Leonard Mdzinarishvili

We investigate local-global principles for Galois cohomology, in the context of function fields of curves over semi-global fields. This extends work of Kato's on the case of function fields of curves over global fields.

Algebraic Geometry · Mathematics 2020-09-30 David Harbater , Daniel Krashen , Alena Pirutka

Let K be a non-archimedean local field. This paper gives an explicit isomorphism between the dual of the special representation of GL_{n+1}(K)$and the space of harmonic cochains defined on the Bruhat-Tits building of GL_{n+1}(K), the…

Group Theory · Mathematics 2019-11-13 Yacine Ait Amrane

Our aim in this paper is to prove in the setting of Kato-Milne cohomology in characteristic 2 an exact sequence which is analogue to the Milnor-Scharlau sequence [8, Theorem 6.2]. This is an extension of the Milnor exact sequence proved in…

Commutative Algebra · Mathematics 2025-04-23 Ahmed Laghribi , Trisha Maiti

Assuming the Bloch-Kato Conjecture, we determine precise conditions under which Hilbert 90 is valid for Milnor k-theory and Galois cohomology. In particular, Hilbert 90 holds for degree n when the cohomological dimension of the Galois group…

Number Theory · Mathematics 2010-02-10 Nicole Lemire , Jan Minac , Andrew Schultz , John Swallow

We prove that the Milnor ring of any (one-dimensional) local or global field K modulo a prime number l is a Koszul algebra over Z/l. Under mild assumptions that are only needed in the case l=2, we also prove various module Koszulity…

K-Theory and Homology · Mathematics 2014-07-15 Leonid Positselski

The Milnor conjecture has been a driving force in the theory of quadratic forms over fields, guiding the development of the theory of cohomological invariants, ushering in the theory of motivic cohomology, and touching on questions ranging…

Algebraic Geometry · Mathematics 2014-06-17 Asher Auel
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