Research shows no dual solutions for Lorentzian cost functions in general, but proves their existence under certain conditions.
problem Existence of dual solutions for Lorentzian cost functions in optimal transportation problems.
method Analyzes dual problem in Lorentz-Finsler geometry, proves existence under natural assumptions, and shows implications for optimal transport.
result Existence of dual solutions under specific conditions, implying timelike optimal transport on a set of full measure.
Researchers found the longest arcs for specific sub-Lorentzian structures.
problem Finding the longest arcs for sub-Lorentzian structures.
method Optimal control problem with unbounded control set and concave cost functional. Sufficient conditions for existence of longest arcs proposed.
result Existence of the longest arcs for left-invariant three-dimensional contact sub-Lorentzian structures proved.
Study timelike Ricci curvature bounds via optimal transport with Orlicz-type costs.
problem Characterize timelike Ricci curvature bounds.
method Optimal transport with Orlicz-type costs, convexity of relative entropy.
result Characterize timelike Ricci curvature lower bounds via convexity of relative entropy.
The Lorentzian length, which is one of the most significant functions in Lorentzian geometry, is a complex-valued function. Its square gives a real-valued non-degenerate quadratic function. In this paper, we define naturally extended mappings of Lorentzian distance-squared functions, wherein each component is a Lorentz…
Solves optimal transport in Lorentz-Finsler spacetimes, generalizing previous work.
problem Optimal transport in Lorentz-Finsler geometry.
method Solves the Kantorovich and Monge problems for globally hyperbolic Lorentz-Finsler spacetimes.
result Generalizes previous results on optimal transport in spacetimes.
Study optimal transport on globally hyperbolic spacetimes, focusing on weak Kantorovich potentials' regularity.
problem Investigate regularity of weak Kantorovich potentials on globally hyperbolic spacetimes.
method Apply insights from Riemannian and Lorentzian cases to study π-solutions. result Conclude existence, uniqueness, and structure of optimal transport maps.
It is commonly known that in Riemannian and sub-Riemannian Geometry, the metric tensor on a manifold defines a distance function. In Lorentzian Geometry, instead of a distance function it provides causal relations and the Lorentzian time-separation function. Both lead to the definition of the Alexandrov topology, which…
Proves limit curve theorem for incomplete metric spaces, applies to null distance in Lorentzian manifolds.
problem Control of Lorentzian lengths of limit curves in incomplete metric spaces.
method Proves limit curve theorem for incomplete metric spaces and applies to null distance.
result Strong control on Lorentzian lengths of limit curves in Sormani and Vegas' null distance.
Formula for sectional curvature on 2D Lorentzian manifolds derived.
problem Calculating sectional curvature on 2D Lorentzian manifolds.
method Obtained a formula for sectional curvature.
result Formula for sectional curvature on 2D Lorentzian manifolds.
Defines Lorentzian distance on contactomorphisms, proving continuity and finite conditions.
problem Continuous distance function on contactomorphisms with finite intervals.
method Defining and analyzing Lorentzian distance functions, proving continuity and finite intervals.
result Distance function is continuous and finite if and only if contactomorphisms are orderable.
We define the notions of St1×Ss1-valued lightcone Gauss maps, lightcone pedal surface and Lorentzian lightcone height function of Lorentzian surface in semi-Euclidean 4-space and established the relationships between singularities of these objects and geometric invariants of the surface as applications of s…
We show that finiteness of the Lorentzian distance is equivalent to the existence of generalised time functions with gradient uniformly bounded away from light cones. To derive this result we introduce new techniques to construct and manipulate achronal sets. As a consequence of these techniques we obtain a functional …
Paper introduces a new time separation function for C0 spacetimes.
problem Lower semicontinuity of time separation function for C0 spacetimes. method Introduced nearly timelike curves to ensure lower semicontinuity.
result Lower semicontinuous time separation function for C0 spacetimes. Study light ray transform on Lorentzian manifolds without conjugate points.
problem Recovering spacelike singularities from weighted light ray transforms.
method Fourier Integral Operator analysis and filtered back-projection.
result Recovery of spacelike singularities from weighted light ray transforms without conjugate points.
Lorentzian distances to Cauchy surfaces fail to be locally equi-Lipschitz.
problem Lorentzian distances to Cauchy surfaces
method Conjectures based on Cauchy temporal functions
result Lorentz distances to Cauchy surfaces are not locally equi-Lipschitz
Study establishes time functions in Lorentzian spaces without requiring manifold structure.
problem Existence and properties of time functions in Lorentzian spaces.
method Characterization of time functions by K-causality, modified volume functions, and global hyperbolicity.
result No manifold structure is needed for suitable time functions in Lorentzian spaces.
Formula derived for curvature on smooth manifolds.
problem Calculating curvature on smooth manifolds.
method Derived a formula for sectional curvature.
result Formula for sectional curvature on smooth manifolds.
Develops optimal transport in Lorentzian spaces with synthetic curvature bounds.
problem Synthetic curvature bounds for Lorentzian spaces.
method Optimal transport, convexity analysis of entropy functionals.
result Synthetic notion of timelike Ricci curvature lower bounds.
New functions linked to curvature bounds in Lorentzian manifolds.
problem Curvature bounds in Lorentzian manifolds and their relation to convex functions.
method Established a connection between sectional curvature bounds and space-time convex and λ-convex functions. result Natural construction of space-time convex and λ-convex functions. The paper solves orbital integrals on Lorentzian symmetric spaces.
problem Determining a function in terms of its orbital integrals on Lorentzian symmetric spaces.
method Extending Helgason's and Orloff's methods to odd-dimensional isotropic Lorentzian symmetric spaces and studying orbital integrals on solvable ones.
result An inversion formula for orbital integrals on solvable Lorentzian symmetric spaces.
The paper explores the injectivity of the light ray transform on Lorentzian manifolds.
problem Injectivity of the light ray transform on functions and tensors.
method Analyzes injectivity conditions for scalar and tensor fields on stationary and static Lorentzian manifolds.
result Injectivity of the light ray transform on functions and tensors is proven under specific conditions.
Study optimal transport on null hypersurfaces and null energy condition.
problem Optimal transport degeneracy on null hypersurfaces.
method Developed tools to characterize null energy condition using convexity properties of entropy.
result Optimal transport characterization of null energy condition.
Study on f-maximal graphs in a Lorentzian product, proving Bernstein theorem.
problem Characterize f-maximal graphs in a Lorentzian product. method Comparison of f-volumes and Bernstein theorem. result Essential condition on gradient for Bernstein theorem.
We study sub-Riemannian and sub-Lorentzian geometry on the Lie group $\SU(1,1)$ and on its universal cover $\CSU(1,1)$. In the sub-Riemannian case we find the distance function and completely describe sub-Riemannian geodesics on both $\SU(1,1)$ and $\CSU(1,1)$, connecting two fixed points. In particular, we prove that …
We introduce a version of Aubry-Mather theory for the length functional of causal curves in compact Lorentzian manifolds. Results include the existence of maximal invariant measures, calibrations and calibrated curves. We prove two versions of the Mather's graph theorem. A class of examples, the Lorentzian Hedlund exam…
New curvature bounds defined for Lorentzian spaces.
problem Establishing equivalence of different curvature definitions for Lorentzian spaces.
method Introducing new curvature concepts based on convexity/concavity and four-point conditions.
result Equivalence of causal and timelike curvature bounds.
Synthetic proof shows globally hyperbolic Lorentzian spaces with specific curvature are warped products.
problem Synthetic proof of rigidity for globally hyperbolic Lorentzian spaces.
method Synthetic geometry and warped product analysis.
result Spaces with specific curvature and distance realizer are warped products.
Study left invariant Lorentzian metrics on 3D non-unimodular Lie groups.
problem Classify and analyze left invariant Lorentzian metrics on 3D non-unimodular Lie groups.
method Classify metrics up to automorphism, study curvature functions.
result Obtain Ricci operator, scalar curvature, and sectional curvatures as functions of metrics.
Study on recovering Lorentzian metrics from scattering data.
problem Recovering Lorentzian metrics from scattering data on a boundary.
method Analyzing the role of boundary distance functions and linearizing the light ray transform.
result Scattering rigidity can be reduced to boundary rigidity of magnetic systems.
Synthetic approach to conformal transformations in metric and Lorentzian spaces.
problem Defining consistent conformal transformations in spaces of low regularity.
method Introducing conformal transformations in metric and Lorentzian spaces, focusing on Lorentzian pre-length spaces.
result Established a consistent notion of conformal length and proved its properties.
We study the weighted ray transform of integrating functions on a Lorentzian manifold over lightlike geodesics. We prove support theorems if the manifold and the weight are analytic.
We prove that an isometric immersion of a simply connected Lorentzian surface in R2,2 is equivalent to a normalised spinor field solution of a Dirac equation on the surface. Using the quaternions and the Lorentz numbers, we also obtain an explicit representation formula of the immersion in terms of the sp…
Study geometrical properties of oscillator group with a Lorentzian metric.
problem Geometrical analysis of oscillator group.
method Bi-invariant Lorentzian metric, homogeneous Ricci solitons, harmonicity properties, energy functional.
result Determination of critical points for energy functional and explicit calculation of their energy.
It is shown that locally conformally flat Lorentzian gradient Ricci solitons are locally isometric to a Robertson-Walker warped product, if the gradient of the potential function is non null, and to a plane wave, if the gradient of the potential function is null. The latter gradient Ricci solitons are necessarily stead…
The strong maximum principle is proved to hold for weak (in the sense of support functions) sub- and super-solutions to a class of quasi-linear elliptic equations that includes the mean curvature equation for C0 spacelike hypersurfaces in a Lorentzian manifold. As one application a Lorentzian warped product splittin…
Globalisation theorem for Lorentzian spaces with curvature bounds.
problem Synthetic geometric analysis of Lorentzian length spaces.
method Cat's cradle construction and synthetic geometry.
result An analogue of Toponogov's Globalisation Theorem for Lorentzian length spaces.
Proves embedding of metric spaces into Lorentzian space.
problem Embedding length metric spaces isometrically.
method Proves approximate isometric embedding into Lorentzian space.
result Every proper n-dimensional length metric space can be embedded approximately.
Study of convergence in Lorentzian spacetimes using temporal functions.
problem Non-compactness of spacetime isometries and convergence in semi-Riemannian settings.
method Introduced anchored convergence and used Cauchy temporal functions to define convergence for spacetimes.
result Established local and global regularity of Cauchy temporal functions and their properties.
Study of recurrent Lorentzian Weyl spaces with detailed local and global structures.
problem Characterizing and classifying non-closed Lorentzian Weyl manifolds.
method Analyzing curvature tensors, Lie group actions, and differential invariants.
result Locally homogeneous non-closed recurrent Lorentzian Weyl manifolds are classified.
The paper characterizes global hyperbolicity in Lorentzian manifolds without relying on manifold topology.
problem Characterizing global hyperbolicity in smooth Lorentzian manifolds without assuming manifold topology.
method Two formulations of global hyperbolicity: one using chronological diamonds and the other using properties of the Lorentzian distance function.
result The second formulation is equivalent to the definition of `Lorentzian metric space' and introduces the concept of d-reflectivity. The null energy condition is characterized via convexity of entropy in Lorentzian manifolds.
problem Characterizing the null energy condition in Lorentzian manifolds.
method Characterization via convexity of the relative entropy along displacement interpolations on null hypersurfaces.
result The null energy condition is characterized in terms of convexity of the relative entropy.
Paper introduces a new convergence for Lorentzian spaces using causal diamonds.
problem No specific problem stated; focuses on a new geometric convergence.
method Uses causal diamonds to define a new convergence for Lorentzian spaces.
result Proves a pre-compactness theorem for Lorentzian spaces.
Exploring distance functions on spacetime models.
problem No canonical distance function exists for Lorentzian manifolds.
method Comparing Riemannianization and null distance function approaches.
result Concrete comparison of distance functions in GRW setting.
The paper constructs Gromov-Hausdorff metrics for Lorentzian spaces and calculates dimensions.
problem Understanding the geometry and dimensions of Lorentzian spaces.
method Construction of Gromov-Hausdorff metrics, calculation of dimensions, and analysis of Lorentzian spaces.
result Dushnik-Miller dimension of Minkowski spaces is countably infinite.
The paper finds a Weierstrass representation for a specific type of Lorentzian minimal surface.
problem Minimal Lorentzian surfaces in R24 with certain curvature conditions. method Weierstrass representation with respect to isothermal and canonical parameters.
result Explicit solution to the system of natural PDEs for general type surfaces.
Introduces length space theory in Lorentzian geometry.
problem Developing length space theory in Lorentzian geometry.
method Formulates concepts using time separation function and synthetic curvature bounds.
result Reveals fundamental results in greater generality.
I introduce a family of closeness functions between causal Lorentzian geometries of finite volume and arbitrary underlying topology. When points are randomly scattered in a Lorentzian manifold, with uniform density according to the volume element, some information on the topology and metric is encoded in the partial or…
Study of Riemann solitons and η-hyperbolic Ricci solitons on Bochner-flat Lorentzian Kähler spacetime manifolds.
problem Analyzing soliton behaviors on Bochner-flat Lorentzian Kähler spacetime manifolds.
method Deriving explicit formulas for soliton parameters and analyzing their behaviors.
result Criteria for shrinking, steady, and expanding behaviors of solitons.