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We show that the category of affine bundles over a smooth manifold M is equivalent to the category of affine spaces modelled on projective finitely generated C^\infty(M)-modules. Using this equivalence of categories, we are able to give an…

Differential Geometry · Mathematics 2012-01-30 Thomas Leuther

We prove that a smooth and connected algebraic group $G$ is affine if and only if any invertible sheaf on any normal $G$-variety is $G$-invariant. For the proof, a key ingredient is the following result: if $G$ is a connected and smooth…

Algebraic Geometry · Mathematics 2024-10-18 C. Sancho de Salas , F. Sancho de Salas , J. B. Sancho de Salas

The classification of local Artinian Gorenstein algebras is equivalent to the study of orbits of a certain non-reductive group action on a polynomial ring. We give an explicit formula for the orbits and their tangent spaces. We apply our…

Commutative Algebra · Mathematics 2016-10-13 Joachim Jelisiejew

Let A be a finitely generated associative algebra over an algebraically closed field. We characterize the finite dimensional modules over A whose orbit closures are regular varieties.

Algebraic Geometry · Mathematics 2007-05-23 Nguyen Quang Loc , Grzegorz Zwara

Invariant affine reflection algebras are the last and the most general known extension of affine Kac-Moody Lie algebras, introduced in recent years. We develop a method known as "affinization" to the class of invariant affine reflection…

Quantum Algebra · Mathematics 2011-09-01 Saeid Azam , S. Reza Hosseini , Malihe Yousofzadeh

Let w be an elliptic element of the Weyl group of a connected reductive group G. Let X be the set of pairs (g,B) where g is an element of G, B is a Borel subgroup of G and B,gBg^{-1} are in relative position w. Then G acts naturally on X.…

Representation Theory · Mathematics 2011-01-11 G. Lusztig

We explore connected affine algebraic groups $G$, which enjoy the following finiteness property $\rm (F)$: for every algebraic action of $G$, the closure of every $G$-orbit contains only finitely many $G$-orbits. We obtain two main results.…

Algebraic Geometry · Mathematics 2020-04-16 Vladimir L. Popov

We discuss the classification of reflection subgroups of finite and affine Weyl groups from the point of view of their root systems. A short case free proof is given of the well known classification of the isomorphism classes of reflection…

Group Theory · Mathematics 2009-09-03 M. J. Dyer , G. I. Lehrer

We show that the classification of simple finite group schemes over an algebraically closed field reduces to the classification of abstract simple finite groups and of simple restricted Lie algebras in positive characteristic. Both these…

Algebraic Geometry · Mathematics 2015-03-13 Filippo Viviani

We study the affine ring of the affine Jacobi variety of a hyper-elliptic curve. The matrix construction of the affine hyper-elliptic Jacobi varieties due to Mumford is used to calculate the character of the affine ring. By decomposing the…

Mathematical Physics · Physics 2009-10-31 A. Nakayashiki , F. A. Smirnov

A connected component of an affine algebraic group is called periodic if all its elements have finite order. We give a characterization of periodic components in terms of automorphisms with finite number of fixed points. It is also…

Algebraic Geometry · Mathematics 2015-05-13 S. N. Fedotov

In this paper, we classify the finite dimensional irreducible modules for affine BMW algebra over an algebraically closed field with arbitrary characteristic.

Quantum Algebra · Mathematics 2012-06-19 Hebing Rui

We are interested in abstract conditions that characterize homomorphic images of affine quandles. Our main result is a two-fold characterization of this class: one by a property of the displacement group, the other one by a property of the…

Group Theory · Mathematics 2020-06-11 Přemysl Jedlička , David Stanovský

We study equivariant affine embeddings of homogeneous spaces and their equivariant automorphisms. An example of a quasiaffine, but not affine, homogeneous space with finitely many equivariant automorphisms is presented. We prove the…

Algebraic Geometry · Mathematics 2009-10-03 Ivan V. Arzhantsev , Dmitri A. Timashev

In this note we show that groups with definable generics in a separably closed valued of finite imperfection degree can be embedded into groups definable in their algebraic closure.

Logic · Mathematics 2017-11-07 Silvain Rideau

The goal of this paper is to provide a method, based on the theory of extensions of left-symmetric algebras, for classifying left-invariant affine structures on a given solvable Lie group of low dimension. To better illustrate our method,…

Differential Geometry · Mathematics 2013-05-01 Mohammed Guediri

I extend the framework of rigid analytic geometry to the setting of algebraic geometry relative to monoids, and study the associated notions of separated, proper, and overconvergent morphisms. The category of affine manifolds embeds as a…

Algebraic Geometry · Mathematics 2015-05-29 Andrew W. Macpherson

A variety is a category of ordered (finitary) algebras presented by inequations between terms. We characterize categories enriched over the category of posets which are equivalent to a variety. This is quite analogous to Lawvere's classical…

Category Theory · Mathematics 2023-04-03 Jiří Adámek , Jiří Rosický

In this work we show that the homogeneous space of an affine algebraic group $G$ by a one-dimensional unipotent subgroup $H$ is affine if and only if the subgroup is not contained in any reductive subgroup of $G$.

Algebraic Geometry · Mathematics 2007-10-02 Alexey V. Petukhov

In this note, we show that the epimorphic subgroups of an algebraic group are exactly the pull-backs of the epimorphic subgroups of its affinization. We also obtain epimorphicity criteria for subgroups of affine algebraic groups, which…

Algebraic Geometry · Mathematics 2017-01-04 Michel Brion