On the exponential map of borei subgroups in a semi-simple lie group

1984 ◽  
Vol 15 (3-4) ◽  
pp. 285-312
Author(s):  
Hsin Chu
Keyword(s):  
Lie Group ◽  
Exponential Map

On the Group of Almost Periodic Diffeomorphisms and its Exponential Map

2019 ◽  
Author(s):  
Xu Sun ◽  
Peter Topalov
Keyword(s):  
Lie Group ◽  
Riemannian Metric ◽  
Conjugate Points ◽  
Exponential Map ◽  
Almost Periodic ◽  
Exponential Maps ◽  
Fluid Equations ◽  
Periodic Diffeomorphisms

Abstract We define the group of almost periodic diffeomorphisms on $\mathbb{R}^n$ and on an arbitrary Lie group. We then study the properties of its Riemannian and Lie group exponential maps and provide applications to fluid equations. In particular, we show that there exists a geodesic of a weak Riemannian metric on the group of almost periodic diffeomorphisms of the line that consists entirely of conjugate points.

Conjugacy Classes of Maximal Tori in Simple Real Algebraic Groups and Applications

1994 ◽  
Vol 46 (4) ◽  
pp. 699-717 ◽  
Author(s):  
Dragomir Ž. Doković ◽  
Nguyêñ Quôć Thăńg
Keyword(s):  
Lie Algebras ◽  
Lie Group ◽  
Short Proof ◽  
Algebraic Groups ◽  
Conjugacy Classes ◽  
Exponential Map ◽  
Simple Complex ◽  
Maximal Tori ◽  
Cartan Subalgebras

AbstractLet G be an almost simple complex algebraic group defined over R, and let G(R) be the group of real points of G. We enumerate the G(R)-conjugacy classes of maximal R-tori of G. Each of these conjugacy classes is also a single G(R)˚-conjugacy class, where G(R)˚ is the identity component of G(R), viewed as a real Lie group. As a consequence we also obtain a new and short proof of the Kostant-Sugiura's theorem on conjugacy classes of Cartan subalgebras in simple real Lie algebras.A connected real Lie group P is said to be weakly exponential (w.e.) if the image of its exponential map is dense in P. This concept was introduced in [HM] where also the question of identifying all w.e. almost simple real Lie groups was raised. By using a theorem of A. Borel and our classification of maximal R-tori we answer the above question when P is of the form G(R)˚.

scholarly journals Geometric Interpretation of a Non-Linear Beam Finite Element on The Lie Group SE(3)

2014 ◽  
Vol 61 (2) ◽  
pp. 305-329 ◽  
Author(s):  
Valentin Sonneville ◽  
Alberto Cardona ◽  
Olivier Brüls
Keyword(s):  
Finite Element ◽  
Rigid Body ◽  
Lie Group ◽  
Geometric Interpretation ◽  
Invariance Property ◽  
Exponential Map ◽  
Element Formulation ◽  
Equilibrium Equations ◽  
Geometrically Exact Beam ◽  
Rigid Body Motions

Abstract Recently, the authors proposed a geometrically exact beam finite element formulation on the Lie group SE(3). Some important numerical and theoretical aspects leading to a computationally efficient strategy were obtained. For instance, the formulation leads to invariant equilibrium equations under rigid body motions and a locking free element. In this paper we discuss some important aspects of this formulation. The invariance property of the equilibrium equations under rigid body motions is discussed and brought out in simple analytical examples. The discretization method based on the exponential map is recalled and a geometric interpretation is given. Special attention is also dedicated to the consistent interpolation of the velocities.

scholarly journals A note on the exponential map of a real or p-adic Lie group

1994 ◽  
Vol 96 (2) ◽  
pp. 113-132 ◽  
Author(s):  
Lawrence Corwin ◽  
Martin Moskowitz
Keyword(s):  
Lie Group ◽  
Exponential Map

Implementation Details of a Generalized-α Differential-Algebraic Equation Lie Group Method

2016 ◽  
Vol 12 (2) ◽  
Author(s):  
Martin Arnold ◽  
Stefan Hante
Keyword(s):  
Algebraic Equation ◽  
Lie Group ◽  
Group Structure ◽  
Time Integration ◽  
Constrained Systems ◽  
Group Method ◽  
Exponential Map ◽  
Differential Algebraic Equation ◽  
Group Setting ◽  
Cosserat Rod

Configuration spaces with Lie group structure display kinematical nonlinearities of mechanical systems. In Lie group time integration, this nonlinear structure is also considered at the time-discrete level using nonlinear updates of the configuration variables. For practical implementation purposes, these update formulae have to be adapted to each specific Lie group setting that may be characterized from the algorithmic viewpoint by group operation, exponential map, tilde, and tangent operator. In this paper, we discuss these practical aspects for the time integration of a geometrically exact Cosserat rod model with rotational degrees-of-freedom being represented by unit quaternions. Shearing and longitudinal extension of the Cosserat rod may be neglected using suitable constraints that result in a differential-algebraic equation (DAE) formulation of the beam structure. The specific structure of unconstrained systems and constrained systems is exploited by tailored algorithms for the corrector iteration of the generalized-α Lie group integrator.

scholarly journals POLYNOMIAL COHOMOLOGY AND POLYNOMIAL MAPS ON NILPOTENT GROUPS

2019 ◽  
Vol 62 (3) ◽  
pp. 706-736
Author(s):  
DAVID KYED ◽  
HENRIK DENSING PETERSEN
Keyword(s):  
Lie Group ◽  
Nilpotent Groups ◽  
Group Cohomology ◽  
Exponential Map ◽  
Nilpotent Lie Group ◽  
Polynomial Maps ◽  
Polynomial Coefficients ◽  
Classical Polynomials ◽  
Simply Connected ◽  
Refined Version

AbstractWe introduce a refined version of group cohomology and relate it to the space of polynomials on the group in question. We show that the polynomial cohomology with trivial coefficients admits a description in terms of ordinary cohomology with polynomial coefficients, and that the degree one polynomial cohomology with trivial coefficients admits a description directly in terms of polynomials. Lastly, we give a complete description of the polynomials on a connected, simply connected nilpotent Lie group by showing that these are exactly the maps that pull back to classical polynomials via the exponential map.

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