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Equivariance of linear neural network layers is well studied. In this work, we relax the equivariance condition to only be true in a projective sense. We propose a way to construct a projectively equivariant neural network through building…

Computer Vision and Pattern Recognition · Computer Science 2023-12-21 Georg Bökman , Axel Flinth , Fredrik Kahl

Consider a smooth manifold and an action on it of a compact connected Lie group with a bi-invariant metric. Then, any orbit is an embedded submanifold that is isometric to a normal homogeneous space for the group. In this paper, we…

Differential Geometry · Mathematics 2024-06-17 Dimbihery Rabenoro , Xavier Pennec

In this note, we show a uniqueness result of homogeneous quasimorphisms defined on the universal cover of the symplectic linear group.

Symplectic Geometry · Mathematics 2007-12-12 Gabi Ben Simon , Dietmar A. Salamon

A free action of a finite group on an odd-dimensional sphere is said to be almost linear if the action restricted to each cyclic or 2-hyperelementary subgroup is conjugate to a free linear action. We begin this survey paper by reviewing the…

Geometric Topology · Mathematics 2016-09-07 Hansjorg Geiges , Charles B. Thomas

We prove that all isometric actions of higher rank simple Lie groups and their lattices on arbitrary uniformly convex Banach spaces have a fixed point. This vastly generalises a recent breakthrough of Oppenheim. Combined with earlier work…

Group Theory · Mathematics 2023-03-09 Tim de Laat , Mikael de la Salle

Equifacetal simplices, all of whose codimension one faces are congruent to one another, are studied. It is shown that the isometry group of such a simplex acts transitively on its set of vertices, and, as an application, equifacetal…

Metric Geometry · Mathematics 2007-05-23 Allan L. Edmonds

We construct new families of quasimorphisms on many groups acting on CAT(0) cube complexes. These quasimorphisms have a uniformly bounded defect of 12, and they "see" all elements that act hyperbolically on the cube complex. We deduce that…

Group Theory · Mathematics 2018-06-29 Talia Fernós , Max Forester , Jing Tao

We obtain an explicit characterization of linear maps, in particular, quantum channels, which are covariant with respect to an irreducible representation ($U$) of a finite group ($G$), whenever $U \otimes U^c$ is simply reducible (with…

Quantum Physics · Physics 2017-05-26 Marek Mozrzymas , Michał Studziński , Nilanjana Datta

We prove a decomposition theorem for the equivariant K-theory of actions of affine group schemes G of finite type over a field on regular separated noetherian algebraic spaces, under the hypothesis that the actions have finite geometric…

Algebraic Geometry · Mathematics 2007-05-23 Gabriele Vezzosi , Angelo Vistoli

We develop an elementary method to compute spaces of equivariant maps from a homogeneous space $G/H$ of a Lie group $G$ to a module of this group. The Lie group is not required to be compact. More generally, we study spaces of invariant…

Representation Theory · Mathematics 2024-04-16 Vincent Knibbeler

Motivated by Xia-Zhou's recent work on applying symmetry groups to the N-body problem, we will study relative equilibria of the equilateral triangle and the square configurations under $\alpha$-homogeneous and quasi-homogeneous potentials…

Classical Analysis and ODEs · Mathematics 2022-07-18 Yingli Li

We present alternative postulates for Euclidean geometry whose merit is that they lead to a new class of invariants and associated geometries for real finite-dimensional unital associative algebras.

Rings and Algebras · Mathematics 2025-09-11 Fred Greensite

This article gives an up-to-date account of the theory of discrete group actions on non-Riemannian homogeneous spaces. As an introduction of the motifs of this article, we begin by reviewing the current knowledge of possible global forms of…

Differential Geometry · Mathematics 2011-06-23 Toshiyuki Kobayashi

We present a new simple proof of the fact that certain group manifolds as well as certain homogeneous spaces G/H of dimension 4n admit a quaternionic triple of integrable complex structures that are covariantly constant with respect to the…

Mathematical Physics · Physics 2020-07-15 A. V. Smilga

The equivariant cohomology for actions of compact connected abelian groups and elementary abelian p-groups have been widely studied in the last decades. We study some of these results on actions of finite cyclic groups over a field of…

Algebraic Topology · Mathematics 2022-06-24 Sergio Chaves

In this paper we obtain explicit linear upper bounds for the virtually cyclic dimension of normally poly-surface and normally poly-free groups. Our approach is based on a structural study of the balanced property (L\"uck's Condition~C),…

Group Theory · Mathematics 2026-03-16 Jesús Hernández Hernández , Porfirio Leandro León Álvarez

Every action of a finite group scheme $G$ on a variety admits a projective equivariant model, but not necessarily a normal one. As a remedy, we introduce and explore the notion of $G$-normalization. In particular, every curve equipped with…

Algebraic Geometry · Mathematics 2024-05-21 Michel Brion

This paper provides a characterization of homogeneous curves on a geometric flag manifold which are geodesic with respect to any invariant metric. We call such curves homogeneous equigeodesics. We also characterize homogeneous equigeodesics…

Differential Geometry · Mathematics 2009-07-13 Nir Cohen , Lino Grama , Caio J. C. Negreiros

We classify the transitive, effective, holomorphic actions of connected complex Lie groups on complex surfaces.

Differential Geometry · Mathematics 2019-11-12 Benjamin McKay

In this work we obtain the general form of polynomial mappings that commute with a linear action of a relative symmetry group. The aim is to give results for relative equivariant polynomials that correspond to the results for relative…

Dynamical Systems · Mathematics 2014-11-25 Patricia Hernandes Baptistelli , Miriam Manoel
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