أهدف هذا البحث إلى تقديم معرفة عامة عن نظرية المضلعات الخاصة فينسلر. نقدم ونحل العديد من المضلعات الخاصة الأكثر أهمية والأكثر شيوعا: مينكوفسكية محليا، بيروالد، لاندسبيرغ، لاندسبيرغ عام، $P$-reducible، $C$-reducible، semi-$C$-reducible، quasi-$C$-reducible، $P^{*}$-Finsler، $C^{h}$-recurrent، $C^{v}$-recurrent، $C^{0}$-recurrent، $S^{v}$-recurrent، $S^{v}$-recurrent من الدرجة الثانية، $C_{2}$-like، $S_{3}$-like، $S_{4}$-like، $P_{2}$-like، $R_{3}$-like، $P$-symmetric، $h$-isotropic، من الإزدواج المنحني، من الإزدواج الثابت، من $p$- الإزدواج المنحني، من $s$-$ps$- الإزدواج المنحني. نقدم تعريفات عامة لهذه المضلعات الخاصة فينسلر. وتم العثور على العديد من العلاقات بين أنواع مختلفة من المضلعات الخاصة المناقشة. وتم إثبات العديد من النتائج المحلية المعروفة في الأدب من خلال النظرية العامة وتم الحصول على العديد من النتائج الجديدة. وكثير من الأدوار الجانبية، تم الحصول على معرفة مهمة وخصوصيات متعلقة بالتورش الشبكي والإزدواج المنحني. على الرغم من أن دراستنا كاملة على الشكل العام، نقدم؛ لأغراض المقارنة، ملحقا يقدم النظرية المحلية المقابلة لنهجنا العام وتعريفات محلية للمضلعات الخاصة المناقشة.
The aim of the present paper is to provide a global presentation of the theory of special Finsler manifolds. We introduce and investigate globally (or intrinsically, free from local coordinates) many of the most important and most commonly used special Finsler manifolds: locally Minkowskian, Berwald, Landesberg, general Landesberg, $P$-reducible, $C$-reducible, semi-$C$-reducible, quasi-$C$-reducible, $P^{*}$-Finsler, $C^{h}$-recurrent, $C^{v}$-recurrent, $C^{0}$-recurrent, $S^{v}$-recurrent, $S^{v}$-recurrent of the second order, $C_{2}$-like, $S_{3}$-like, $S_{4}$-like, $P_{2}$-like, $R_{3}$-like, $P$-symmetric, $h$-isotropic, of scalar curvature, of constant curvature, of $p$-scalar curvature, of $s$-$ps$-curvature. The global definitions of these special Finsler manifolds are introduced. Various relationships between the different types of the considered special Finsler manifolds are found. Many local results, known in the literature, are proved globally and several new results are obtained. As a by-product, interesting identities and properties concerning the torsion tensor fields and the curvature tensor fields are deduced. Although our investigation is entirely global, we provide; for comparison reasons, an appendix presenting a local counterpart of our global approach and the local definitions of the special Finsler spaces considered.
In this paper, we prove that lightlike geodesics of a pseudo-Finsler manifold and its focal points are preserved up to reparametrization by anisotropic conformal changes, using the Chern connection and the anisotropic calculus and the fact that geodesics are critical points of the energy functional and Jacobi fields, the kernel of its index form. This result has applications to the study of Finsler spacetimes.
In the standard approach to Finsler geometry the metric is defined as a vertical Hessian and the Chern or Cartan connections appear as just two among many possible natural linear connections on the pullback tangent bundle. Here it is shown that the Hessian nature of the metric, the non-linear connection and the Chern or Cartan connections can be derived from a few compatibility axioms between metric and Finsler connection. This result provides a metric foundation to Finsler geometry and hence justifies the claim that ``Finsler geometry is Riemannian geometry without the quadratic restriction. The paper also contains a study of the compatibility condition to be placed between the metric and the non-linear connection.
In this paper we investigate the spectral problem in Finsler geometry. Due to the nonlinearity of the Finsler-Laplacian operator, we introduce textit{faithful dimension pairs} by means of which the spectrum of a compact reversible Finsler metric measure manifold is defined. Various upper and lower bounds of such eigenvalues are provided in the spirit of Cheng, Buser and Gromov, which extend in several aspects the results of Hassannezhad, Kokarev and Polterovich. Moreover, we construct several faithful dimension pairs based on Lusternik-Schnirelmann category, Krasnoselskii genus and essential dimension, respectively; however, we also show that the Lebesgue covering dimension pair is not faithful. As an application, we show that the Bakry-Emery spectrum of a closed weighted Riemannian manifold can be characterized by the faithful Lusternik-Schnirelmann dimension pair.
In this paper, we study the spectrums of faithful dimension pairs on a closed Finsler manifold and obtain a Gromov type and a Buser type lower bounds for eigenvalues. Furthermore, for the Lusternik-Schnirelmann spectrum, we not only obtain a better lower bound, but also estimate the multiplicity of each eigenvalue.
A systematic study of (smooth, strong) cone structures $C$ and Lorentz-Finsler metrics $L$ is carried out. As a link between both notions, cone triples $(Omega,T, F)$, where $Omega$ (resp. $T$) is a 1-form (resp. vector field) with $Omega(T)equiv 1$ and $F$, a Finsler metric on $ker (Omega)$, are introduced. Explicit descriptions of all the Finsler spacetimes are given, paying special attention to stationary and static ones, as well as to issues related to differentiability. In particular, cone structures $C$ are bijectively associated with classes of anisotropically conformal metrics $L$, and the notion of {em cone geodesic} is introduced consistently with both structures. As a non-relativistic application, the {em time-dependent} Zermelo navigation problem is posed rigorously, and its general solution is provided.