Title
Homogeneous Sobolev Metric of Order One on Diffeomorphism Groups on Real Line.
Abstract
In this article we study Sobolev metrics of order one on diffeomorphism groups on the real line. We prove that the space equipped with the homogeneous Sobolev metric of order one is a flat space in the sense of Riemannian geometry, as it is isometric to an open subset of a mapping space equipped with the flat -metric. Here denotes the extension of the group of all compactly supported, rapidly decreasing, or -diffeomorphisms, which allows for a shift toward infinity. Surprisingly, on the non-extended group the Levi-Civita connection does not exist. In particular, this result provides an analytic solution formula for the corresponding geodesic equation, the non-periodic Hunter–Saxton (HS) equation. In addition, we show that one can obtain a similar result for the two-component HS equation and discuss the case of the non-homogeneous Sobolev one metric, which is related to the Camassa–Holm equation.
Year
DOI
Venue
2014
10.1007/s00332-014-9204-y
Journal of Nonlinear Science
Keywords
DocType
Volume
Diffeomorphism group,Geodesic equation,Sobolev H1-metric,R-map,Primary 35Q31,58B20,58D05
Journal
24
Issue
ISSN
Citations 
5
Journal of Nonlinear Science 24, 5 (2014), 769-808
2
PageRank 
References 
Authors
0.40
3
3
Name
Order
Citations
PageRank
Martin Bauer15210.45
M. Bruveris2584.53
Peter W. Michor3332.36