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A generalization of the term "generalized Clifford algebras" (as appears in papers on advances in applied Clifford algebras) is introduced. This algebra is studied by means of structure theory of central simple algebras. A graph theoretical…

Rings and Algebras · Mathematics 2011-12-09 Adam Chapman

The algebra of supernatural matrices is a key example in the theory of locally finite central simple algebras, which studied in a previous paper of the authors (\cite{Local}). It is also a stand-alone object admits a rich study and various…

Rings and Algebras · Mathematics 2023-11-02 Tamar Bar-On , Shira Gilat , Eli Matzri , Uzi Vishne

By the result of Artin--Tate--Van den Bergh, every $3$-dimensional cubic AS-regular algebra A can be expressed as a geometric algebra $A=\mathcal{A}(E,\sigma)$, where $E$ is either $\mathbb{P}^{1}\times \mathbb{P}^{1}$ or a curve of…

Rings and Algebras · Mathematics 2026-03-31 Ayako Itaba , Masaki Matsuno , Yu Saito

In this Master of Science Thesis I introduce geometric algebra both from the traditional geometric setting of vector spaces, and also from a more combinatorial view which simplifies common relations and operations. This view enables us to…

Rings and Algebras · Mathematics 2008-11-07 Douglas Lundholm

The characterization of commutators in associative algebras is a classical problem in ring theory. In this paper, we address this problem for the natural class of generalized block-triangular algebras. To this end, we introduce a new…

Rings and Algebras · Mathematics 2025-10-08 Pedro Souza Fagundes , Thiago Castilho de Mello

We characterize connected tetravalent graphs $\Gamma$ which admit groups $M<H$ of automorphisms such that $\Gamma$ is $M$-half-arc-transitive and $H$-arc-transitive. Examples for each case are constructed, including a counter-example to a…

Group Theory · Mathematics 2025-12-29 Yuandong Li , Binzhou Xia , Jin-Xin Zhou

We introduce decomposition algebras as a natural generalization of axial algebras, Majorana algebras and the Griess algebra. They remedy three limitations of axial algebras: (1) They separate fusion laws from specific values in a field,…

Rings and Algebras · Mathematics 2020-08-26 Tom De Medts , Simon F. Peacock , Sergey Shpectorov , Michiel Van Couwenberghe

The paper concerns extra special associative algebras, an analogue of the Heisenberg Lie algebra. In particular, we say that an associative algebra is extra special if its center is equal to its derived ideal and the center is…

Rings and Algebras · Mathematics 2022-12-06 Erik Mainellis

Let $A$ be a graded algebra. It is shown that the derived category of dg modules over $A$ (viewed as a dg algebra with trivial differential) is a triangulated hull of a certain orbit category of the derived category of graded $A$-modules.…

Representation Theory · Mathematics 2017-11-27 Martin Kalck , Dong Yang

We construct a class of positive linear maps on matrix algebras. We find conditions when these maps are atomic, decomposable and completely positive. We obtain a large class of atomic positive linear maps. As applications in quantum…

Operator Algebras · Mathematics 2017-04-25 Xin Li , Wei Wu

The paper concerns perfect diassociative algebras and their implications to the theory of central extensions. It is first established that perfect diassociative algebras have strong ties with universal central extensions. Then, using a…

Rings and Algebras · Mathematics 2022-01-19 Erik Mainellis

We study skew-symmetrizable cluster algebras $\mathcal{A}$ associated with unpunctured surfaces $\tilde{\mathbf{S}}$ endowed with an orientation-preserving involution $\sigma$. We give a geometric realization of such cluster algebras by…

Representation Theory · Mathematics 2026-01-16 Azzurra Ciliberti

In his study of the relative Dixmier property for inclusions of von Neumann algebras and of $C^*$-algebras, Popa considered a certain property of automorphisms on $C^*$-algebras, that we here call the strong averaging property. In this note…

Operator Algebras · Mathematics 2023-01-25 Mikael Rørdam

Let $\sigma$ be an automorphism of a field $K$ with fixed field $F$. We study the automorphisms of nonassociative unital algebras which are canonical generalizations of the associative quotient algebras $K[t;\sigma]/fK[t;\sigma]$ obtained…

Rings and Algebras · Mathematics 2021-04-13 Christian Brown , Susanne Pumpluen

A commutative algebra is exact if its multiplication endomorphisms are trace-free and is Killing metrized if its Killing type trace-form is nondegenerate and invariant. A Killing metrized exact commutative algebra is necessarily neither…

Rings and Algebras · Mathematics 2020-05-15 Daniel J. F. Fox

We generalize Abel's classical theorem on linear equivalence of divisors on a Riemann surface. For every closed submanifold $M^d \subset X^n$ in a compact oriented Riemannian $n$--manifold, or more generally for any $d$--cycle $Z$ relative…

Differential Geometry · Mathematics 2008-12-02 Johan L. Dupont , Franz W. Kamber

We construct a generalized version for the free product of unital C*-algebras over a family of unital C*-subalgebras, starting from the group-analogue. When all the subalgebras are the same, we recover the free product with amalgamation…

Operator Algebras · Mathematics 2007-05-23 Stefan Teodor Bildea

For any finite dimensional Lie superalgebra $\dot{\mathfrak{g}}$ (maybe a Lie algebra) with an even derivation $d$ and a finite order automorphism $\sigma$ that commutes with $d$, we introduce the $(d,\sigma)$-twisted Affine-Virasoro…

Representation Theory · Mathematics 2025-07-02 Rencai Lü , Xizhou You , Kaiming Zhao

We introduce regular closed subgraphs of Katsura's topological graphs and use them to generalize the notion of an adjunction space from topology. Our construction attaches a topological graph onto another via a regular factor map. We prove…

Operator Algebras · Mathematics 2025-07-15 Atul Gothe , John Quigg , Mariusz Tobolski

Symmetric edge polytopes are a recent and well-studied family of centrally symmetric polytopes arising from graphs. In this paper, we introduce a generalization of this family to arbitrary simplicial complexes. We show how topological…

Combinatorics · Mathematics 2026-02-20 Torben Donzelmann , Thiago Holleben , Martina Juhnke