Homogenisation on homogeneous spaces
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Accepted version
Author(s)
Li, Xue-Mei
Type
Journal Article
Abstract
Motivated by collapsing of Riemannian manifolds and inhomogeneous
scaling of left invariant Riemannian metrics on a real Lie group $G$
with a sub-group $H$, we introduce a family of interpolation equations
on $G$ with a parameter $\epsilon>0$, interpolating hypo-elliptic
diffusions on $H$ and translates of exponential maps on $G$ and
examine the dynamics as $\epsilon\to 0$. When $H$ is compact, we use
the reductive homogeneous structure of Nomizu to extract a converging
family of stochastic processes (converging on the time scale
$1/\epsilon$), proving the convergence of the stochastic dynamics on
the orbit spaces $G/H$ and their parallel translations, providing also
an estimate on the rate of the convergence in the Wasserstein
distance. Their limits are not necessarily Brownian motions and are
classified algebraically by a Peter-Weyl's theorem for real Lie groups
and geometrically using a weak notion of the naturally reductive
property; the classifications allow to conclude the Markov property of
the limit process. This can be considered as "taking the adiabatic
limit" of the differential operators
$\mathcal{L}^\epsilon=(1/\epsilon) \sum_k (A_k)^2+(1/\epsilon)
A_0+Y_0$ where $Y_0, A_k$ are left invariant vector fields and
$\{A_k\}$ generate the Lie-algebra of $H$.
scaling of left invariant Riemannian metrics on a real Lie group $G$
with a sub-group $H$, we introduce a family of interpolation equations
on $G$ with a parameter $\epsilon>0$, interpolating hypo-elliptic
diffusions on $H$ and translates of exponential maps on $G$ and
examine the dynamics as $\epsilon\to 0$. When $H$ is compact, we use
the reductive homogeneous structure of Nomizu to extract a converging
family of stochastic processes (converging on the time scale
$1/\epsilon$), proving the convergence of the stochastic dynamics on
the orbit spaces $G/H$ and their parallel translations, providing also
an estimate on the rate of the convergence in the Wasserstein
distance. Their limits are not necessarily Brownian motions and are
classified algebraically by a Peter-Weyl's theorem for real Lie groups
and geometrically using a weak notion of the naturally reductive
property; the classifications allow to conclude the Markov property of
the limit process. This can be considered as "taking the adiabatic
limit" of the differential operators
$\mathcal{L}^\epsilon=(1/\epsilon) \sum_k (A_k)^2+(1/\epsilon)
A_0+Y_0$ where $Y_0, A_k$ are left invariant vector fields and
$\{A_k\}$ generate the Lie-algebra of $H$.
Date Issued
2018
Date Acceptance
2017-02-03
Citation
Journal of Mathematical Society of Japan, 2018, 70 (2), pp.519-572
ISSN
0025-5645
Publisher
Mathematical Society of Japan
Start Page
519
End Page
572
Journal / Book Title
Journal of Mathematical Society of Japan
Volume
70
Issue
2
Copyright Statement
© Mathematical Society of Japan. Reuse is permitted for education, research and other academic purposes
Identifier
https://projecteuclid.org/euclid.jmsj/1524038666#info
Subjects
General Mathematics
0101 Pure Mathematics
Publication Status
Published
Date Publish Online
2018-04-18