The study explores Einstein Kropina metrics on Lie groups and homogeneous spaces.
problem Investigating Einstein Kropina metrics on Lie groups and homogeneous spaces.
method Constructing Einstein Kropina metrics on Lie groups and homogeneous spaces using specific procedures.
result Classification and construction of Einstein Kropina metrics on various Lie groups and homogeneous spaces.
The study finds homogeneous geodesics in homogeneous Kropina spaces.
problem Existence of homogeneous geodesics in homogeneous Kropina spaces.
method Analyzes homogeneous Kropina spaces and (α,β)-homogeneous spaces to find geodesics. result Homogeneous Kropina spaces admit at least one homogeneous geodesic through any point.
Calculates S-curvature and mean Berwald curvature in homogeneous Finsler spaces.
problem Calculating curvatures in homogeneous Finsler spaces.
method Explicit formula for S-curvature and mean Berwald curvature in homogeneous generalized m-Kropina metric.
result Explicit formula for S-curvature and mean Berwald curvature in homogeneous generalized m-Kropina metric.
Study flag curvature in homogeneous Finsler spaces with a specific metric.
problem Analyzing flag curvature in homogeneous Finsler spaces with a generalized m-Kropina metric. method Provided explicit formula for flag curvature, showed equivalence of definitions, and studied curvature of naturally reductive spaces.
result Equivalence of two definitions of naturally reductive homogeneous Finsler spaces for the generalized m-Kropina metric. In the present article we compute the flag curvature of a special type of invariant Kropina metrics on homogeneous spaces.
Using the navigation data (h,W) of a Kropina space, we characterize weakly-Berwald Kropina spaces and Berwald Kropina spaces by means of the Killing vector field W and the parallel vector field W, respectively. Moreover, the local 1-parameter group of Finslerian local isometries of the Kropina space coincides with the …
Study geodesics on strong Kropina spaces, global and local aspects.
problem Geodesics behavior on strong Kropina spaces.
method Global and local analysis of geodesics.
result Illustrated geodesics with examples.
Paper finds conditions for generalized Kropina spaces to have constant curvature.
problem Classifying Finsler spaces of constant curvature.
method Obtained necessary and sufficient conditions for generalized Kropina spaces to be of constant flag curvature.
result Conditions for generalized Kropina spaces to have constant curvature.
The paper explores conditions for projective and dually flat metrics in Finsler spaces with Kropina changes of mth-root metrics.
problem Conditions for projective and dually flat metrics in Finsler spaces with Kropina changes of mth-root metrics.
method Analyzes conditions for projective and dually flat metrics in Finsler spaces with Kropina changes of mth-root metrics.
result Conditions for projective and dually flat metrics in Finsler spaces with Kropina changes of mth-root metrics are identified.
Study minimal surfaces in Kropina 3D space, finding only planes as minimal translation surfaces.
problem Characterizing minimal surfaces in Kropina 3D space.
method Solving partial differential equations to characterize minimal surfaces.
result Only planes are minimal translation surfaces in Kropina 3D space.
The present paper studies globally defined Kropina metrics as solutions of the Zermelo's navigation problem. Moreover, we characterize the Kropina metrics of constant flag curvature showing that up to local isometry, there are only two model spaces of them: the Euclidean space and the odd-dimensional spheres.
In this paper conditions for a Kropina structure to be of constant flag curvature are obtained.
The concept of h-vector was introduced by H. Izumi in 1980. Recently we have obtained the Cartan connection for the Finsler space whose metric is given by Kropina change with an h-vector. In 1985, M. Matsumoto studied the theory of Finsler hypersurface. In this paper, we derive certain geometrical properties of a Finsl…
Study on metrizability and Ricci-flatness of Finsler spaces with Kropina metrics.
problem Investigating metrizability and Ricci-flatness of Finsler spaces with specific metrics.
method Analyzing the Levi-Civita connection, covariant derivative of 1-forms, and using cohomology groups.
result Explicitly obtained all Ricci-flat, locally metrizable m-Kropina metrics in (3+1)D.
Study canonical curves and Kropina metrics in Lagrangian contact geometry.
problem Characterize canonical curves and their relationship to Lagrangian contact structures.
method Construct Fefferman-type spaces, analyze chains and null-chains, use Kropina metrics, apply Fermat principle.
result Chains and null-chains in integrable Lagrangian contact structures are geodesics of Kropina metrics.
Einstein-Kropina metrics extend Einstein condition to all signatures and classify Finsler gravity solutions.
problem Einstein-Kropina metrics in Finsler gravity
method Generalize Einstein condition and classify solutions
result All Einstein-Kropina solutions to the Λ-vacuum equation are Berwald and Ricci-flat, with vanishing cosmological constant. In this paper, we discuss the Finsler spaces (Mn,L) and (Mn,∗L), where ∗L(x,y) is obtained from L(x,y) by Kropina change ∗L(x,y)=bi(x,y)yiL2(x,y) and bi(x,y) is an h-vector in (Mn,L). We find the necessary and sufficient condition when the Cartan connection coefficients…
The paper studies Kropina metrics with a specific curvature property.
problem Characterizing Kropina metrics with isotropic scalar curvature.
method Tensor analysis to derive expressions and characterize metrics.
result Characterization of Kropina metrics with isotropic scalar curvature.
Study investigates metrizability of Finsler spaces with specific metrics.
problem Local metrizability of Finsler spaces with m-Kropina metric. method Investigates the local metrizability of Finsler spaces with m-Kropina metric F=α1+mβ−m, where β is a closed null 1-form. result Proves that the affine connection on such an m-Kropina space is locally metrizable by a (pseudo-)Riemannian metric if and only if the Ricci tensor is symmetric. The paper solves navigation problems on conic Kropina manifolds and establishes curvature relationships.
problem Navigation problems on conic Kropina manifolds.
method Analyzes the solution of navigation problems and establishes curvature relationships.
result The solution to navigation problems on conic Kropina manifolds must be either a Randers metric or a Kropina metric.
Study on geodesics in Kropina metrics with applications.
problem Existence of connecting and closed geodesics in Kropina metrics.
method Analytical proofs and applications to null geodesics and navigation problems.
result Proves existence of geodesics in Kropina metrics.
In this paper, a characteristic condition of Einstein Kropina metrics is given. By the characteristic condition, we prove that a non-Riemannian Kropina metric F=βα2 with constant Killing form β on an n-dimensional manifold M, n≥2, is an Einstein metric if and only if α is also an Einstein metric. …
In this paper, we consider Kropina change of m-th root Finsler metrics. We find necessary and sufficient condition under which the Kropina change of an m-th root Finsler metric be locally dually flat. Then we prove that the Kropina change of an m-th root Finsler metric is locally projectively flat if and only if …
In this paper, we consider a special class of singular Finsler metrics: m-Kropina metrics which are defined by a Riemannian metric and a 1-form. We show that an m-Kropina metric (m=−1) of scalar flag curvature must be locally Minkowskian in dimension n≥3. We characterize by some PDEs a Kropina metric ($…
In this paper, a characteristic condition of the projectively flat Kropina metric is given. By it, we prove that a Kropina metric F=α2/β with constant curvature K and ∥β∥α=1 is projectively flat if and only if F is locally Minkowskian.
This paper examines a generalized Kropina metric and its geometric properties.
problem Investigating geometric properties of a generalized Kropina metric.
method Analyzing a Finsler manifold with a concurrent π-vector field and examining the φ-concurrent generalized Kropina change. result The geodesic sprays of the original Finsler metric and the modified metric are never projectively related.
Study on generalized m-Kropina metrics in modified gravity and cosmology.
problem Understanding the geometric properties and applications of generalized m-Kropina metrics. method Proving the rationality of Finslerian geometric objects and studying the conditions for Einstein metrics.
result Conditions for a generalized m-Kropina metric to be an exact solution in modified gravity and cosmology. Singular Finsler metrics, such as Kropina metrics and m-Kropina metrics, have a lot of applications in the real world. In this paper, we classify a class of singular (α,β)-metrics which are locally projectively flat with constant flag curvature in dimension n=2 and n≥3 respectively. Further, we determine t…
Singular Finsler metrics, such as Kropina metrics and m-Kropina metrics, have a lot of applications in the real world. In this paper, we study a class of singular Finsler metrics defined by a Riemann metric α and 1-form β and characterize those which are respectively Douglasian and locally projectively flat in di…
Singular Finsler metrics, such as Kropina metrics and m-Kropina metrics, have a lot of applications in the real world. In this paper, we study a class of two-dimensional singular Finsler metrics defined by a Riemann metric α and 1-form β, and we characterize those which are Douglasian or locally projectively flat…
In this paper, we find the necessary and sufficient conditions under which two classes of (q, a, b)-metrics are projectively related to a Kropina metric.
Chains in CR geometry are geodesics of a Kropina metric.
problem Understanding chains in CR geometry.
method Generalization of Fermat principle and Kropina metric construction.
result Chains determine CR structure up to conjugacy.
The paper studies minimal surfaces in deformed hyperbolic spaces and their properties.
problem Characterizing minimal surfaces in deformed hyperbolic spaces.
method Analyzes minimal surfaces in deformed hyperbolic spaces using partial differential equations and flag curvature.
result Minimal surfaces in deformed hyperbolic spaces have non-positive flag curvature and cannot have conjugate points.
The paper extends Ricci curvature in Finsler geometry and finds conditions for specific metrics.
problem Characterizing and finding conditions for specific metrics in Finsler geometry.
method Introducing weighted projective Ricci curvature and analyzing Randers and Kropina metrics.
result Conditions for metrics to have weighted projective Ricci flat curvature.
Study proves existence of multiple geodesics in a specific metric space.
problem Existence of multiple geodesics in a manifold with a Randers-Kropina metric.
method Lusternik-Schnirelman theory applied to a homotopy type of solutions of an affine control system.
result Proves existence of infinitely many geodesics between two points in a non-contractible manifold.
Study examines causal properties of Finsler spacetimes with cone Killing vectors.
problem Characterize causality in Finsler spacetimes with specific Killing vectors.
method Explores the relationship between wind Riemannian structures and spacetimes with cone Killing vectors, focusing on Finsler-Kropina metrics.
result Characterizes causality properties using metric-type properties of Finslerian structures.
Study weakly weighted Einstein-Finsler metrics, showing specific curvature properties and characterizing them.
problem Characterizing weakly weighted Einstein-Finsler metrics.
method Showed isotropic S-curvature under certain conditions. Characterized via navigation expressions and α and β. result Weakly weighted Einstein-Kropina metrics have isotropic S-curvature and can be completely characterized.
For a standard Finsler metric F on a manifold M, its domain is the whole tangent bundle TM and its fundamental tensor g is positive-definite. However, in many cases (for example, the well-known Kropina and Matsumoto metrics), these two conditions are relaxed, obtaining then either a pseudo-Finsler metric (with arbitrar…
The paper classifies isoparametric hypersurfaces in conic Finsler spaces.
problem Identifying new isoparametric hypersurfaces in conic Finsler spaces.
method Introduced isoparametric functions and hypersurfaces in conic Finsler spaces, classified them in specific spaces.
result Found additional isoparametric hypersurfaces in conic Minkowski spaces, such as helicoids.
The paper shows that almost every path structure is not variational.
problem Determining if a path structure is variational.
method Generalized Douglas's result to higher dimensions and analyzed path geometries with infinitesimal symmetries.
result Almost every path structure is not variational.
We give the explicit formulas of the flag curvatures of left invariant Matsumoto and Kropina metrics of Berwald type. We can see these formulas are different from previous results given recently. Using these formulas, we prove that at any point of an arbitrary connected non-commutative nilpotent Lie group, the flag cur…
We generalize the Zermelo navigation problem and its solution on Riemannian manifolds (M,h) admitting a space dependence of a ship's speed 0<∣u(x)∣h≤1 in the presence of a perturbation W~ determined by a strong velocity vector field satisfying ∣W~(x)∣h=∣u(x)∣h, with application of Finsler m…
Integral formulae for foliated Riemannian manifolds provide obstructions for existence of foliations or compact leaves of them with given geometric properties. Recently, we associated a new Riemannian metric to a codimension-one foliated Finsler space and proved integral formulae for general and for Randers spaces. In …
The paper studies special metrics on tangent Lie groups.
problem Investigating lifted (α,β)-metrics of Douglas type on tangent Lie groups. method Constructing and analyzing vertical and complete lifted (α,β)-metrics on tangent Lie groups. result Necessary and sufficient conditions for these metrics to be of Douglas type are derived.
Paper proves conformal transformation of special (α,β)-metrics to Douglas spaces.
problem Douglas spaces of second kind with (α,β)-metrics and their conformal transformations. method Analyzes and proves conformal transformation of specific (α,β)-metrics to Douglas spaces of second kind. result Proves that certain (α,β)-metrics are conformally transformed to Douglas spaces of second kind. Introduces new types of homogeneous spaces and their properties.
problem Defining and understanding new types of homogeneous spaces.
method Introducing and analyzing (strongly) (Θ-)discrete homogeneous spaces. result Discovers relationships between new and existing homogeneous space types.
Recently, wind Riemannian structures (WRS) have been introduced as a generalization of Randers and Kropina metrics. They are constructed from the natural data for Zermelo navigation problem, namely, a Riemannian metric gR and a vector field W (the wind), where, now, the restriction of mild wind gR(W,W)<1 is dro…
Survey of recent results on homogeneous finite-dimensional spaces.
problem Understanding properties of homogeneous finite-dimensional spaces.
method Discussion of recent results and unsolved problems.
result Discussion of recent results and unsolved problems.