Projective Metrizability and Formal Integrability

The projective metrizability problem can be formulated as follows: under what conditions the geodesics of a given spray coincide with the geodesics of some Finsler space, as oriented curves. In Theorem 3.8 we reformulate the projective metrizability problem for a spray in terms of a first-order part...

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Main Authors: Ioan Bucataru, Zoltán Muzsnay
Format: Article
Language:English
Published: National Academy of Science of Ukraine 2011-12-01
Series:Symmetry, Integrability and Geometry: Methods and Applications
Subjects:
Online Access:http://dx.doi.org/10.3842/SIGMA.2011.114
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author Ioan Bucataru
Zoltán Muzsnay
author_facet Ioan Bucataru
Zoltán Muzsnay
author_sort Ioan Bucataru
collection DOAJ
description The projective metrizability problem can be formulated as follows: under what conditions the geodesics of a given spray coincide with the geodesics of some Finsler space, as oriented curves. In Theorem 3.8 we reformulate the projective metrizability problem for a spray in terms of a first-order partial differential operator P_1 and a set of algebraic conditions on semi-basic 1-forms. We discuss the formal integrability of P_1 using two sufficient conditions provided by Cartan-Kähler theorem. We prove in Theorem 4.2 that the symbol of P_1 is involutive and hence one of the two conditions is always satisfied. While discussing the second condition, in Theorem 4.3 we prove that there is only one obstruction to the formal integrability of P_1, and this obstruction is due to the curvature tensor of the induced nonlinear connection. When the curvature obstruction is satisfied, the projective metrizability problem reduces to the discussion of the algebraic conditions, which as we show are always satisfied in the analytic case. Based on these results, we recover all classes of sprays that are known to be projectively metrizable: flat sprays, isotropic sprays, and arbitrary sprays on 1- and 2-dimensional manifolds. We provide examples of sprays that are projectively metrizable without being Finsler metrizable.
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spelling doaj.art-4b498d5c1e9e4c8fbee42aad317215462022-12-22T00:18:35ZengNational Academy of Science of UkraineSymmetry, Integrability and Geometry: Methods and Applications1815-06592011-12-017114Projective Metrizability and Formal IntegrabilityIoan BucataruZoltán MuzsnayThe projective metrizability problem can be formulated as follows: under what conditions the geodesics of a given spray coincide with the geodesics of some Finsler space, as oriented curves. In Theorem 3.8 we reformulate the projective metrizability problem for a spray in terms of a first-order partial differential operator P_1 and a set of algebraic conditions on semi-basic 1-forms. We discuss the formal integrability of P_1 using two sufficient conditions provided by Cartan-Kähler theorem. We prove in Theorem 4.2 that the symbol of P_1 is involutive and hence one of the two conditions is always satisfied. While discussing the second condition, in Theorem 4.3 we prove that there is only one obstruction to the formal integrability of P_1, and this obstruction is due to the curvature tensor of the induced nonlinear connection. When the curvature obstruction is satisfied, the projective metrizability problem reduces to the discussion of the algebraic conditions, which as we show are always satisfied in the analytic case. Based on these results, we recover all classes of sprays that are known to be projectively metrizable: flat sprays, isotropic sprays, and arbitrary sprays on 1- and 2-dimensional manifolds. We provide examples of sprays that are projectively metrizable without being Finsler metrizable.http://dx.doi.org/10.3842/SIGMA.2011.114spraysprojective metrizabilitysemi-basic formspartial differential operatorsformal integrability
spellingShingle Ioan Bucataru
Zoltán Muzsnay
Projective Metrizability and Formal Integrability
Symmetry, Integrability and Geometry: Methods and Applications
sprays
projective metrizability
semi-basic forms
partial differential operators
formal integrability
title Projective Metrizability and Formal Integrability
title_full Projective Metrizability and Formal Integrability
title_fullStr Projective Metrizability and Formal Integrability
title_full_unstemmed Projective Metrizability and Formal Integrability
title_short Projective Metrizability and Formal Integrability
title_sort projective metrizability and formal integrability
topic sprays
projective metrizability
semi-basic forms
partial differential operators
formal integrability
url http://dx.doi.org/10.3842/SIGMA.2011.114
work_keys_str_mv AT ioanbucataru projectivemetrizabilityandformalintegrability
AT zoltanmuzsnay projectivemetrizabilityandformalintegrability