Homological algebra | Group theory | Cohomology theories | Algebraic number theory

Group cohomology

In mathematics (more specifically, in homological algebra), group cohomology is a set of mathematical tools used to study groups using cohomology theory, a technique from algebraic topology. Analogous to group representations, group cohomology looks at the group actions of a group G in an associated G-module M to elucidate the properties of the group. By treating the G-module as a kind of topological space with elements of representing n-simplices, topological properties of the space may be computed, such as the set of cohomology groups . The cohomology groups in turn provide insight into the structure of the group G and G-module M themselves. Group cohomology plays a role in the investigation of fixed points of a group action in a module or space and the quotient module or space with respect to a group action. Group cohomology is used in the fields of abstract algebra, homological algebra, algebraic topology and algebraic number theory, as well as in applications to group theory proper. As in algebraic topology, there is a dual theory called . The techniques of group cohomology can also be extended to the case that instead of a G-module, G acts on a nonabelian G-group; in effect, a generalization of a module to non-Abelian coefficients. These algebraic ideas are closely related to topological ideas. The group cohomology of a discrete group G is the singular cohomology of a suitable space having G as its fundamental group, namely the corresponding Eilenberg–MacLane space. Thus, the group cohomology of can be thought of as the singular cohomology of the circle S1, and similarly for and A great deal is known about the cohomology of groups, including interpretations of low-dimensional cohomology, functoriality, and how to change groups. The subject of group cohomology began in the 1920s, matured in the late 1940s, and continues as an area of active research today. (Wikipedia).

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Paul GUNNELLS - Cohomology of arithmetic groups and number theory: geometric, ... 2

In this lecture series, the first part will be dedicated to cohomology of arithmetic groups of lower ranks (e.g., Bianchi groups), their associated geometric models (mainly from hyperbolic geometry) and connexion to number theory. The second part will deal with higher rank groups, mainly

From playlist École d'Été 2022 - Cohomology Geometry and Explicit Number Theory

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Aurel PAGE - Cohomology of arithmetic groups and number theory: geometric, ... 2

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From playlist École d'Été 2022 - Cohomology Geometry and Explicit Number Theory

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From playlist Abstract algebra

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Paul GUNNELLS - Cohomology of arithmetic groups and number theory: geometric, ... 1

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From playlist École d'Été 2022 - Cohomology Geometry and Explicit Number Theory

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From playlist Summer of Math Exposition Youtube Videos

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From playlist Abstract algebra

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Aurel PAGE - Cohomology of arithmetic groups and number theory: geometric, ... 1

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From playlist École d'Été 2022 - Cohomology Geometry and Explicit Number Theory

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From playlist Group theory

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From playlist Mathematics

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From playlist Vortex Moduli - 2023

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Cup Products in Automorphic Cohomology - Matthew Kerr

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From playlist Mathematics

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From playlist Mathematics

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From playlist Algebraic geometry: extra topics

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From playlist Algebraic and Complex Geometry

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Galilean group cohomology in classical mechanics

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From playlist Algebra

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From playlist Infosys-ICTS Ramanujan Lectures

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Jacek Brodzki (6/30/17) Bedlewo: The Geometry of Synchronization Problems and Learning Group Act

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From playlist Applied Topology in Będlewo 2017

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From playlist HIM Lectures: Junior Trimester Program "Topology"

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From playlist 2022 Summer School on the Langlands program

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