English
Related papers

Related papers: Twisted actions of categorical groups

200 papers

We give a simple construction involving partial actions which permits us to obtain an easy proof of a weakened version of L. O'Carroll's theorem on idempotent pure extensions of inverse semigroups.

Group Theory · Mathematics 2018-04-06 Mykola Khrypchenko

In this paper, we construct a partial group \(\mathcal{P}(F)\) that represents the "partial symmetry" inherent in a subset \(F\) of \(d\)-dimensional Euclidean space. In cases where \(F\) is not connected, \(\mathcal{P}(F)\) captures more…

Group Theory · Mathematics 2025-08-27 Takahiro Hayashi

Let G be a group and let P be a subsemigroup of G. In order to describe the crossed product of a C*-algebra A by an action of P by unital endomorphisms we find that we must extend the action to the whole group G. This extension fits into a…

Operator Algebras · Mathematics 2010-03-16 Ruy Exel

In this paper, we develop a semi-classical analysis on H-type groups. We define semi-classical pseudodifferential operators, prove the boundedness of their action on square integrable functions and develop a symbolic calculus. Then, we…

Functional Analysis · Mathematics 2018-12-04 Clotilde Fermanian-Kammerer , Veronique Fischer

We give a unified description of twisted forms of classical reductive groups schemes. Such group schemes are constructed from algebraic objects of finite rank, excluding some exceptions of small rank. These objects, augmented odd form…

Group Theory · Mathematics 2026-05-08 Egor Voronetsky

We use the geometry of the space of fields for gauged supersymmetric mechanics to construct the twisted differential equivariant K-theory of a manifold with an action by a finite group.

Algebraic Topology · Mathematics 2015-10-28 Daniel Berwick-Evans

We investigate Moufang loops which can be written as the semidirect product of a loop and a group. We also examine a particular class of loop extensions which arise as a result of a finite cyclic group acting as a group of semiautomorphisms…

Group Theory · Mathematics 2015-02-24 Mark Greer , Lee Raney

In this paper, we will introduce a novel method for constructing numerous examples of twisted partial Hopf actions. Utilizing split quaternions, split semi-quaternions, and ${1\over4}$-quaternions as our subjects of study, we have obtained…

Rings and Algebras · Mathematics 2025-07-29 Chen Quanguo

In this paper we define twisted equivariant K-theory for actions of Lie groupoids. For a Bredon-compatible Lie groupoid, this defines a periodic cohomology theory on the category of finite CW-complexes with equivariant stable projective…

Algebraic Topology · Mathematics 2011-05-18 Jose Cantarero

We establish an isomorphism between the center of the twisted Heisenberg category and the subalgebra of the symmetric functions $\Gamma$ generated by odd power sums. We give a graphical description of the factorial Schur $Q$-functions as…

Representation Theory · Mathematics 2018-07-17 Henry Kvinge , Can Ozan Oğuz , Michael Reeks

We formulate an alternative approach to describing Ehresmann semigroups by means of left and right \'etale actions of a meet semilattice on a category. We also characterize the Ehresmann semigroups that arise as the set of all subsets of a…

Category Theory · Mathematics 2021-04-21 Mark V Lawson

We introduce a natural pseudometric on the space of actions of d-generated groups. In this pseudometric, the zero classes correspond to the weak equivalence classes defined by Kechris, and the metric identification is compact. We achieve…

Functional Analysis · Mathematics 2025-03-18 Miklos Abert , Gabor Elek

Twisted \'etale groupoid algebras have been studied recently in the algebraic setting by several authors in connection with an abstract theory of Cartan pairs of rings. In this paper, we show that extensions of ample groupoids correspond in…

Rings and Algebras · Mathematics 2021-01-26 Benjamin Steinberg

Motivated by some alternatives to the classical logical model of boolean algebra, this paper deals with algebraic structures which extend skew lattices by locally invertible elements. Following the meme of the Ehresmann-Schein-Nambooripad…

Group Theory · Mathematics 2021-01-07 D. G. FitzGerald

We develop a Galois theory of commutative rings under actions of finite inverse semigroups. We present equivalences for the definition of Galois extension as well as a Galois correspondence theorem. We also show how the theory behaves in…

Rings and Algebras · Mathematics 2025-01-03 Wesley G. Lautenschlaeger , Thaísa Tamusiunas

In the context of finite tensor products of Hilbert spaces, we prove that similarity of a tensor product of operator semigroups to a contraction semigroup is equivalent to the corresponding similarity for each factor, after an appropriate…

Functional Analysis · Mathematics 2025-09-04 J. Oliva-Maza , Y. Tomilov

Given an inverse semigroup $S$ endowed with a partial action on a topological space $X$, we construct a groupoid of germs $S\ltimes X$ in a manner similar to Exel's groupoid of germs, and similarly a partial action of $S$ on an algebra $A$…

Rings and Algebras · Mathematics 2019-10-14 Luiz Gustavo Cordeiro , Viviane Beuter

We introduce a category of inverse semigroup actions and a category of \'etale groupoids. We show that there are three functors which send inverse semigroups to their spectral actions, inverse semigroup actions to their transformation…

Operator Algebras · Mathematics 2024-10-29 Takuto Fujieda , Takeshi Katsura , Tomoki Uchimura

We define twisted equivariant K-homology groups using geometric cycles. We compare them with approaches using Kasparov KK-Theory and (twisted) group C*-algebras.

K-Theory and Homology · Mathematics 2015-01-27 Noe Barcenas

In this article, we introduce the concept of partial actions of a group $G$ on quivers and demonstrate that for any given partial action of G on a quiver $\Gamma$, there exists another quiver, $\Gamma'$ with a full $G$-action. This is an…

Representation Theory · Mathematics 2025-10-27 Wagner Cortes , Eduardo N. Marcos
‹ Prev 1 3 4 5 6 7 10 Next ›