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In this paper, we introduce a symmetric continuous cohomology of topological groups. This is obtained by topologizing a recent construction due to Staic (J. Algebra 322 (2009), 1360-1378), where a symmetric cohomology of abstract groups is…

Group Theory · Mathematics 2013-06-04 Mahender Singh

Cosetal extensions of monoids generalise extensions of groups, special Schreier extensions of monoids and Leech's normal extensions of groups by monoids. They share a number of properties with group extensions, including a notion of Baer…

Rings and Algebras · Mathematics 2022-01-19 Peter Faul , Graham Manuell

Centers of categories capture the natural operations on their objects. Homotopy coherent centers are introduced here as an extension of this notion to categories with an associated homotopy theory. These centers can also be interpreted as…

Algebraic Topology · Mathematics 2019-04-12 Markus Szymik

We study the second bounded cohomology of an amalgamated free product of groups, and an HNN extension of a group. As an application, we have a group with infinitely many ends has infinite dimensional second bounded cohomology.

Group Theory · Mathematics 2008-02-03 Koji Fujiwara

The article is devoted to a structure of topological spaces related with topological quasigroups. Regular and complete spaces over topological quasigroups are studied. Separations and embeddings are also investigated for them. Their…

Group Theory · Mathematics 2023-12-29 S. V. Ludkowski

The classifying space of a crossed complex generalises the construction of Eilenberg-Mac Lane spaces. We show how the theory of fibrations of crossed complexes allows the analysis of homotopy classes of maps from a free crossed complex to…

Algebraic Topology · Mathematics 2008-06-25 Ronald Brown

We give an overview of various prolongations of quasigroups. Two step prolongation procedure is proposed.

Group Theory · Mathematics 2015-07-22 V. A. Shcherbacov

Basing ourselves on the categorical notions of central extensions and commutators in the framework of semi-abelian categories relative to a Birkhoff subcategory, we study central extensions of Leibniz algebras with respect to the Birkhoff…

Rings and Algebras · Mathematics 2015-11-11 J. M. Casas , E. Khmaladze

We introduce a notion of equivariant coarse cohomology of the complement of a subspace in a metric space. We use this cohomology to define a notion of coarse cohomology of the configuration space of a metric space and develop tools to…

Metric Geometry · Mathematics 2025-11-05 Arka Banerjee

The purpose of this paper is to introduce an algebraic cohomology and formal deformation theory of left alternative algebras. Connections to some other algebraic structures are given also.

Rings and Algebras · Mathematics 2016-10-17 Mohamed Elhamdadi , Abdenacer Makhlouf

The purpose of this paper is to study global deformations of Hom-Leibniz algebras. We introduce a cohomology for Hom-Leibniz algebras with values in a Hom-module, characterize versal deformations and provide examples.

Rings and Algebras · Mathematics 2013-03-01 Faouzi Ammar , Zeyneb Ejbehi , Abdenacer Makhlouf

The most general possible central extensions of two whole families of Lie algebras, which can be obtained by contracting the special pseudo-unitary algebras su(p,q) of the Cartan series A_l and the pseudo-unitary algebras u(p,q), are…

Mathematical Physics · Physics 2008-11-26 F. J. Herranz , J. C. Pérez Bueno , M. Santander

Every ring extension of $A$ by $R$ induces a pair of group homomorphisms $\mathcal{L}^{*}:R\to End_\Z(A)/L(A);\mathcal{R}^{*}:R\to End_\Z(A)/R(A),$ preserving multiplication, satisfying some certain conditions. A such 4-tuple…

Category Theory · Mathematics 2007-06-05 Nguyen Tien Quang , Nguyen Thu Thuy

The Johnson filtration of the mapping class group of a compact, oriented surface is the descending series consisting of the kernels of the actions on the nilpotent quotients of the fundamental group of the surface. Each term of the Johnson…

Group Theory · Mathematics 2018-08-10 Kazuo Habiro , Gwenael Massuyeau

An explicit construction of a pre-quantum line bundle for the moduli space of flat G-bundles over a Riemann surface is given, where G is any non-simply connected compact simple Lie group. This work helps to explain a curious coincidence…

Symplectic Geometry · Mathematics 2010-09-21 Derek Krepski

We compare three different ways of defining group cohomology with coefficients in a crossed-module: 1) explicit approach via cocycles; 2) geometric approach via gerbes; 3) group theoretic approach via butterflies. We discuss the case where…

K-Theory and Homology · Mathematics 2010-01-26 Behrang Noohi

We introduce the concept of Hom-associative algebra structures in Loday-Pirashvili category.The cohomology theory of Hom-associative algebras in this category is studied.Some applications on deformation and abelian extension theory are…

Rings and Algebras · Mathematics 2024-05-28 Tao Zhang

We survey decades of research identifying the (co)homology of configuration spaces with Lie algebra (co)homology. The different routes to this one proto-theorem offer genuinely different explanations of its truth, and we attempt to convey…

Algebraic Topology · Mathematics 2025-08-21 Ben Knudsen

We develop an obstruction theory for the existence of gauge equivalences in complete differential graded Lie algebras. Specifically, this theory provides a characterization of homotopy equivalences between differential graded algebras…

Algebraic Topology · Mathematics 2025-09-23 Coline Emprin

We prove an extension criterion for codimension one foliations on projective hypersurfaces based on the degree of the foliation and the degree of the hypersurface, and we ensure, in some instances, an isomorphism between the corresponding…

Algebraic Geometry · Mathematics 2023-08-10 Mateus Gomes Figueira