Relative geodesics in bi-invariant Lie groups

E. Zhang, L. Noakes

    Research output: Contribution to journalArticle

    Abstract

    Motivated by registration problems, this paper deals with a curve matching problem in homogeneous spaces. Let G be a connected finite-dimensional bi-invariant Lie group and K a closed subgroup. A smooth curve g in G is said to be admissible if it can transform two smooth curves f1 and f2 in G/K from one to the other. An (f1, f2)-relative geodesic (Holm et al. 2013 Proc. R. Soc. A 469, 20130297. (doi:10.1098/rspa.2013.0297)) is defined as a critical point of the total energy E(g) as g varies in the set of all (f1, f2)-admissible curves. We obtain the Euler-Lagrange equation, a first-order differential equation, satisfied by a relative geodesic. Furthermore, the Euler-Lagrange equation is simplified for the case where G/K is globally symmetric. As a concrete example, relative geodesics are found for special cases where G is SO(3) and K is SO(2). As an application of discrepancy for curves in S2, we construct and study a new measure of non-congruency for constant speed curves in Euclidean 3-space. Numerical examples are given to illustrate results.

    Original languageEnglish
    Article number20160619
    JournalProceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences
    Volume473
    Issue number2201
    DOIs
    Publication statusPublished - 1 May 2017

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