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We give a complete description of the category of smooth complex representations of the multiplicative group of a central simple algebra over a locally compact nonarchimedean local field. More precisely, for each inertial class in the…

Representation Theory · Mathematics 2010-09-07 Vincent Sécherre , Shaun Stevens

We study here systems of symmetries on $|1|$--graded parabolic geometries. We are interested in smooth systems of symmetries and we discuss non--flat homogeneous $|1|$--graded geometries. We show the existence of an invariant admissible…

Differential Geometry · Mathematics 2010-01-26 Lenka Zalabova

In this article, we define amorphic complexity for actions of locally compact $\sigma$-compact amenable groups on compact metric spaces. Amorphic complexity, originally introduced for $\mathbb Z$-actions, is a topological invariant which…

Dynamical Systems · Mathematics 2023-03-15 Gabriel Fuhrmann , Maik Gröger , Tobias Jäger , Dominik Kwietniak

Let G(A) be an AF-algebra given by periodic Bratteli diagram with the incidence matrix A in GL(n, Z). For a given polynomial p(x) in Z[x] we assign to G(A) a finite abelian group Z^n/p(A) Z^n. It is shown that if p(0)=1 or p(0)=-1 and…

Number Theory · Mathematics 2014-07-14 Igor Nikolaev

We introduce a new class of finite dimensional gentle algebras, the surface algebras, which are constructed from an unpunctured Riemann surface with boundary and marked points by introducing cuts in internal triangles of an arbitrary…

Representation Theory · Mathematics 2011-04-05 Lucas David-Roesler , Ralf Schiffler

For an algebraically closed field K, let G be a finite abelian group of K-linear automorphisms of a finite-dimensional path algebra KQ of a quiver Q. Under certain assumptions on the action of G, we show the existence of a certain kind of…

Representation Theory · Mathematics 2025-07-29 Shantanu Sardar , Alfredo Gonzalez Chaio , Sonia Trepode

We consider smooth representations of the unit group $G = \mathcal{A}^{\times}$ of a finite-dimensional split basic algebra $\mathcal{A}$ over a non-Archimedean local field. In particular, we prove a version of Gutkin's conjecture, namely,…

Representation Theory · Mathematics 2019-11-01 Carlos A. M. André , João Dias

We generalise the definition of a group algebra so that it makes sense for non-locally compact topological groups, in particular, we require that the representation theory of the group algebra is isomorphic (in the sense of Gelfand-Raikov)…

Operator Algebras · Mathematics 2007-05-23 Hendrik Grundling

Over a non-closed field, it is a common strategy to use separable algebras as invariants to distinguish algebraic and geometric objects. The most famous example is the deep connection between Severi-Brauer varieties and central simple…

Algebraic Geometry · Mathematics 2024-02-26 Matthew R. Ballard , Alexander Duncan , Alicia Lamarche , Patrick K. McFaddin

The subject matter of this paper is the geometry of the affine group over the integers, $\mathsf{GL}(n,\mathbb{Z})\ltimes \mathbb{Z}^n$. Turing-computable complete $\mathsf{GL}(n,\mathbb{Z})\ltimes \mathbb{Z}^n$-orbit invariants are…

Dynamical Systems · Mathematics 2019-02-05 Daniele Mundici

Smooth K-functors are introduced and the smooth K-theory of locally convex algebras is developed. It is proved that the algebraic and smooth K-functors are isomorphic on the category of quasi stable real (or complex) Frechet algebras.

K-Theory and Homology · Mathematics 2007-05-23 H. Inassaridze , T. Kandelaki

We study graph products of groups from the viewpoint of measured group theory. We first establish a full measure equivalence classification of graph products of countably infinite groups over finite simple graphs with no transvection and no…

Group Theory · Mathematics 2024-01-10 Amandine Escalier , Camille Horbez

This paper concerns the compactness and separability properties of the normed Boolean algebras (N.B.A.) with respect to topology generated by a distance equal to the square root of a measure of symmetric difference between two elements. The…

General Topology · Mathematics 2022-02-08 Vesna Gotovac Đogaš

We address the question of identifying non-smooth points in affine real algebraic varieties. A simple algebraic criterion will be formulated and proven. As an application we can answer several questions about the configuration spaces of…

Algebraic Geometry · Mathematics 2019-08-07 Marc Diesse

We give a necessary and sufficient smoothness condition for the scheme parameterizing the n-dimensional representations of a finitely generated associative algebra over an algebraically closed field of characteristic zero. In particular,…

Algebraic Geometry · Mathematics 2015-10-26 Alessandro Ardizzoni , Federica Galluzzi , Francesco Vaccarino

Let G be a finite group acting by automorphism on a lattice A, and hence on the group algebra S=k[A]. The algebra of G-invariants in S is called an algebra of multiplicative invariants. We investigate when algebras of multiplicative…

Commutative Algebra · Mathematics 2007-05-23 Martin Lorenz

We will show that separable unital AF-algebras whose Bratteli diagrams do not allow converging two nodes into one node, can be classified up to the tensor product with the universal UHF-algebra $\Q$ only by their trace spaces. That is, if…

Operator Algebras · Mathematics 2020-09-11 Saeed Ghasemi

Fiber bundles over infinite fields with non-trivial ultra-norms are considered. For them geometric wrap groups are defined and investigated. Besides fields also Cayley-Dickson algebras over fields of characteristic not equal to two are…

Group Theory · Mathematics 2018-12-18 S. V. Ludkovsky

In this paper which is the first of a series of papers on smooth structures, the concepts of C-structures and smooth structures are introduced and studied. The notion of smooth structure on semi-integral domains is given. It is shown that…

Commutative Algebra · Mathematics 2010-09-23 Ahmad Shafiei Deh Abad

Let $X$ be a smooth compact manifold and $v$ a vector field on $X$ which admits a smooth function $f: X \to \mathbf R$ such that $df(v) > 0$. Let $\partial X$ be the boundary of $X$. We denote by $C^\infty(X)$ the algebra of smooth…

Geometric Topology · Mathematics 2023-03-02 Gabriel Katz