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Related papers: Relative cohomology theory for profinite groups

200 papers

We define two different versions of the relative De Rham cohomology groups of a diffeological space. Additionally, we study a variant of the Mayer-Vietoris sequence and discuss the existence of a relative cup product. Our approach is…

Algebraic Topology · Mathematics 2024-12-19 Enrique Macías-Virgós , Reihaneh Mehrabi

The theory of intersection spaces assigns cell complexes to certain stratified topological pseudomanifolds depending on a perversity function in the sense of intersection homology. The main property of the intersection spaces is Poincar\'e…

Algebraic Topology · Mathematics 2018-12-03 J. Timo Essig

A group $\Gamma$ has separable cohomology if the profinite completion map $\iota \colon \Gamma \to \widehat{\Gamma}$ induces an isomorphism on cohomology with finite coefficient modules. In this article, cohomological separability is…

Group Theory · Mathematics 2024-06-07 William D. Cohen , Julian Wykowski

We define the profinite completion of a C*-algebra, which is a pro-C*-algebra, as well as the pro-C*-algebra of a profinite group. We show that the continuous representations of the pro-C*-algebra of a profinite group correspond to the…

Operator Algebras · Mathematics 2012-04-23 Rachid El Harti , N. Christopher Phillips , Paulo R. Pinto

Poincare duality lies at the heart of the homological theory of manifolds. In the presence of the action of a group it is well-known that Poincare duality fails in Bredon's ordinary, integer-graded equivariant homology. We give here a…

Algebraic Topology · Mathematics 2013-12-03 Steven R. Costenoble , Stefan Waner

Motivated by orbifold string theory, we introduce orbifold cohomology group for any almost complex orbifold and orbifold Dolbeault cohomology for any complex orbifold. Then, we show that our new cohomology group satisfies Poincare duality…

Algebraic Geometry · Mathematics 2009-10-31 Weimin Chen , Yongbin Ruan

A combination of Bestvina--Brady Morse theory and an acyclic reflection group trick produces a torsion-free finitely presented Q-Poincar\'e duality group which is not the fundamental group of an aspherical closed ANR Q-homology manifold.…

Geometric Topology · Mathematics 2012-04-23 Jim Fowler

We study profinite completion of spaces in the model category of profinite spaces and construct a rigidification of the completion functors of Artin-Mazur and Sullivan which extends also to non-connected spaces. Another new aspect is an…

Algebraic Topology · Mathematics 2011-11-21 Gereon Quick

$p$-Adic compactifications of geometric loop and diffeomorphism groups of compact manifolds on finite-dimensional spaces over non-Archimedean fields are investigated. Weakened topology is introduced. The structure of newly constructed…

Group Theory · Mathematics 2007-05-23 S. Ludkovsky , B. Diarra

We say that a group $G$ is of \textit{profinite type} if it can be realized as a Galois group of some field extension. Using Krull's theory, this is equivalent to the ability of $G$ to be equipped with a profinite topology. We also say that…

Group Theory · Mathematics 2024-03-14 Tamar Bar-On , Nikolay Nikolov

We establish results concerning the profinite completions of 3-manifold groups. In particular, we prove that the complement of the figure-eight knot $S^3-K$ is distinguished from all other compact 3-manifolds by the set of finite quotients…

Geometric Topology · Mathematics 2015-06-01 Martin R Bridson , Alan W Reid

We generalize basic results relating the associated graded Lie algebra and the holonomy Lie algebra from finitely presented, commutator-relators groups to arbitrary finitely presented groups. In the process, we give an explicit formula for…

Geometric Topology · Mathematics 2019-03-06 Alexander I. Suciu , He Wang

Rational discrete cohomology and homology for a totally disconnected locally compact group $G$ is introduced and studied. The $\mathrm{Hom}$-$\otimes$ identities associated to the rational discrete bimodule $\mathrm{Bi}(G)$ allow to…

Group Theory · Mathematics 2021-01-22 Ilaria Castellano , Thomas Weigel

In this series of three papers, we introduce and study cyclotomic pairs and smooth profinite groups. They are a geometric axiomatisation of Kummer theory for fields, with coefficients $p$-primary roots of unity, for a prime $p$. These…

Algebraic Geometry · Mathematics 2025-03-19 Charles De Clercq , Mathieu Florence

We have generalised the notion of categorical theory in model theory to the context of coherent theories. We prove a duality result between the full sub-2-category of pretopoi which are categorical, and the 2-category of profinite monoids.…

Category Theory · Mathematics 2026-05-22 Lingyuan Ye

We undertake the study of profinite quandles. We provide several constructions of profinite quandles from profinite groups, and from other profinite quandle. We characterize which subquandles of profinite quandles are again profinite.…

Geometric Topology · Mathematics 2024-11-05 Alexander W. Byard , Brian Cai , Nathan P. Jones , Lucy H. Vuong , David N. Yetter

In the case of a compact orientable pseudomanifold, a well-known theorem of M. Goresky and R. MacPherson says that the cap product with a fundamental class factorizes through the intersection homology groups. In this work, we show that this…

Algebraic Topology · Mathematics 2017-05-22 David Chataur , Martintxo Saralegi-Aranguren , Daniel Tanré

We introduce a notion of Poincar\'e duality for pairs of $\infty$-categories, extending Poincar\'e-Lefschetz duality for pairs of spaces. This categorical extension yields an efficient book-keeping device that affords, among other things, a…

Algebraic Topology · Mathematics 2025-10-24 Andrea Bianchi , Kaif Hilman , Dominik Kirstein , Christian Kremer

A group $G$ is said to be a $C$-group if every subgroup $H$ has a permutable complement, i.e. if there exists a subgroup $K$ of $G$ such that $G=HK$ and $H \cap K=1$. In this paper, we study the profinite counterpart of this concept. We say…

Group Theory · Mathematics 2025-07-29 Gustavo A. Fernández-Alcober , Giulia Sabatino

This paper explores the cup and cap products within the cohomology and homology groups of ample groupoids, focusing on their applications and fundamental properties. Ample groupoids, which are \'etale groupoids with a totally disconnected…

Operator Algebras · Mathematics 2025-06-25 Hiroki Matui , Takehiko Mori