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Principal homogeneous space

Related publications (22)

Global Frobenius liftability I

We formulate a conjecture characterizing smooth projective varieties in positive characteristic whose Frobenius morphism can be lifted modulo p(2)-we expect that such varieties, after a finite stale cover, admit a toric fibration over an ordinary abelian v ...

2021

Orders That Are Etale-Locally Isomorphic

Eva Bayer Fluckiger, Mathieu Huruguen

Let R be a semilocal Dedekind domain with fraction field F. It is shown that two hereditary R-orders in central simple F-algebras that become isomorphic after tensoring with F and with some faithfully flat etale R-algebra are isomorphic. On the other hand, ...

AMER MATHEMATICAL SOC2020

A General Theory of Equivariant CNNs on Homogeneous Spaces

Mario Geiger

We present a general theory of Group equivariant Convolutional Neural Networks (G-CNNs) on homogeneous spaces such as Euclidean space and the sphere. Feature maps in these networks represent fields on a homogeneous base space, and layers are equivariant ma ...

NEURAL INFORMATION PROCESSING SYSTEMS (NIPS)2019

Orders that are étale-locally isomorphic

Eva Bayer Fluckiger, Mathieu Huruguen

Let R be a semilocal Dedekind domain with fraction field F. It is shown that two hereditary R-orders in central simple F-algebras that become isomorphic after tensoring with F and with some faithfully flat étale R-algebra are isomorphic. On the other hand, ...

2019

Hyperbolicity as an obstruction to smoothability for one-dimensional actions

Yash Lodha

Ghys and Sergiescu proved in the 1980s that Thompson's group T, and hence F, admits actions by C-infinity diffeomorphisms of the circle. They proved that the standard actions of these groups are topologically conjugate to a group of C-infinity diffeomorphi ...

GEOMETRY & TOPOLOGY PUBLICATIONS2019

Modular functors, cohomological field theories, and topological recursion

Nicolas Gerson Orantin

Given a topological modular functor V in the sense of Walker, we construct vector bundles Z (lambda) over bar, over (M) over bar (g,n) whose Chern characters define semi-simple cohomological field theories. This construction depends on a determinati ...

AMER MATHEMATICAL SOC2018

Optimal regionalization of extreme value distributions for flood estimation

Anthony Christopher Davison, Sebastian Engelke, Peiman Asadi

Regionalization methods have long been used to estimate high return levels of river discharges at ungauged locations on a river network. In these methods, discharge measurements from a homogeneous group of similar, gauged, stations are used to estimate hig ...

2018

Influence of heterogeneities on crack propagation

Jean-François Molinari, Okan Yilmaz, Jérémy Bleyer

The influence of material heterogeneities is studied in the context of dynamic failure. We consider a pre-strained plate problem, the homogeneous case of which has been widely studied both experimentally and numerically. This setup is used to isolate the e ...

2018

Fixed Points For Bounded Orbits In Hilbert Spaces

Nicolas Monod, Maxime Gheysens

Consider the following property of a topological group G: every continuous affine G-action on a Hilbert space with a bounded orbit has a fixed point. We prove that this property characterizes amenability for locally compact a-compact groups (e.g., countabl ...

2017

On sums of eigenvalues of elliptic operators on manifolds

Joachim Stubbe

We use the averaged variational principle introduced in a recent article on graph spectra [10] to obtain upper bounds for sums of eigenvalues of several partial differential operators of interest in geometric analysis, which are analogues of Kroger's bound ...

European Mathematical Soc2017

Eigenfunction expansions of ultradifferentiable functions and ultradistributions

Aparajita Dasgupta

In this paper we give a global characterisation of classes of ultradi_erentiable functions and corresponding ultradistributions on a compact manifold X. The characterisation is given in terms of the eigenfunction expansion of an elliptic operator on X. Thi ...

2016

Special Reductive Groups Over An Arbitrary Field

Mathieu Huruguen

A linear algebraic group G defined over a field k is called special if every G-torsor over every field extension of k is trivial. In 1958 Grothendieck classified special groups in the case where the base field is algebraically closed. In this paper we desc ...

Springer Birkhauser2016

Embedding functor for classical groups and Brauer–Manin obstruction

Eva Bayer Fluckiger, Ting-Yu Lee

Let K be a global field of characteristic not 2. The embedding problem for maximal tori in a classical group G can be described in terms of algebras with involution. The aim of this paper is to give an explicit description of the obstruction group to the H ...

2015

Confined vortices in topologically massive U(1) x U(1) theory

Mikhail Chapochnikov, Yannis Burnier, Eray Sabancilar

We report on a new topological vortex solution in U(1) x U(1) Maxwell-Chern-Simons theory. The existence of the vortex is envisaged by analytical means, and a numerical solution is obtained by integrating the equations of motion. These vortices have a long ...

American Physical Society2015

Balanced Fiber Bundles and GKM Theory

Silvia Sabatini

Let T be a torus and B a compact T-manifold. Goresky et al. show in [3] that if B is (what was subsequently called) a GKM manifold, then there exists a simple combinatorial description of the equivariant cohomology ring H-T*(B) as a subring of H-T*(B-T). I ...

Oxford University Press2013

Analysis of human brain exposure to low-frequency magnetic fields: A numerical assessment of spatially averaged electric fields and exposure limits

Juan Ramon Mosig, Valerio De Santis, Nicolas Chavannes

Compliance with the established exposure limits for the electric field (E-field) induced in the human brain due to low-frequency magnetic field (B-field) induction is demonstrated by numerical dosimetry. The objective of this study is to investigate the de ...

Wiley-Blackwell2013

A Real-Time Deformable Detector

Pascal Fua, François Fleuret, Karim Ali, David Hasler

We propose a new learning strategy for object detection. The proposed scheme forgoes the need to train a collection of detectors dedicated to homogeneous families of poses, and instead learns a single classifier that has the inherent ability to deform base ...

Institute of Electrical and Electronics Engineers2012

Generalized Euler-Poincar, Equations on Lie Groups and Homogeneous Spaces, Orbit Invariants and Applications

Feride Tiglay

We develop the necessary tools, including a notion of logarithmic derivative for curves in homogeneous spaces, for deriving a general class of equations including Euler-Poincar, equations on Lie groups and homogeneous spaces. Orbit invariants play an impor ...

Springer Netherlands2011

Dirac Group(oid)s and Their Homogeneous Spaces

Madeleine Jotz

A theorem of Drinfel'd (Drinfel'd (1993)) classifies the Poisson homogeneous spaces of a Poisson Lie group (G,πG) via a special class of Lagrangian subalgebras of the Drinfel'd double of its Lie bialgebra. This result is extended in Liu et al. (1998) to a ...

EPFL2011

Existence Of Guided Cylindrical Tm-Modes In An Inhomogeneous Self-Focusing Dielectric

Charles Stuart

We consider an eigenvalue problem for a certain type of quasi-linear second-order differential equation on the interval (0, infinity). Using an appropriate version of the mountain pass theorem, we establish the existence of a positive solution in H-0(1)(0, ...

2010