Historical income per capita data follow hyperbolic growth patterns.
problem Economic stagnation and Malthusian traps in historical data.
method Fitting hyperbolic distributions to GDP/capita and population data.
result Income per capita growth was monotonic and without transitions.
Unified Growth Theory contradicted by Latin American economic data.
problem Unified Growth Theory fails to explain Latin American economic growth.
method Analysis of historical economic growth data from Maddison.
result Unified Growth Theory is inconsistent with Latin American data.
A statistical analysis of financial, economic, and demographic indicators performed by the authors demonstrates (1) that the main countries of East Africa (Uganda, Kenya, and Tanzania) have not escaped the Malthusian Trap yet; (2) that this countries are not likely to follow the "North African path" and to achieve this…
The study examines how individualism and collectivism affect economic outcomes.
problem Understanding how societal norms impact economic performance and inequality.
method Dynamic model analyzing the effects of individualism and collectivism on economic outcomes during the Malthusian Era.
result More individualistic societies have smaller populations, higher per capita income, and greater income inequality.
The Unified Growth Theory is a puzzling collection of myths based on illusions created by hyperbolic distributions. Some of these myths are discussed. The examination of data shows that the three stages of growth (Malthusian Regime, Post-Malthusian Regime and Modern Growth Regime) did not exist and that Industrial Revo…
Unified Growth Theory contradicted by Asian economic data.
problem Unified Growth Theory fails to explain Asian economic growth.
method Analysis of historical economic growth data in Asia.
result Asian economic growth was hyperbolic, not stagnant.
Unified Growth Theory contradicted by USSR economic data.
problem Unified Growth Theory fails to explain USSR economic growth.
method Analysis of historical USSR economic data.
result USSR economic growth was hyperbolic, not stagnant.
Study shows no closed trapped submanifolds can be tangent to certain spacelike hypersurfaces.
problem Existence of closed trapped submanifolds in spacetime regions foliated by specific hypersurfaces.
method Introduced k−future convex spacelike/null hypersurfaces and proved no k−dimensional closed trapped submanifolds can be tangent to these hypersurfaces from their future side. result Closed trapped submanifolds cannot be found in open spacetime regions foliated by k−future convex hypersurfaces. Study analyzes household capital risk and poverty trapping, deriving a new function for capital deficit distribution.
problem Analyzing the risk of household capital falling into poverty.
method Introduced a new Gerber-Shiu function to model trapping time and capital deficit distribution.
result Derived a model for capital deficit distribution at trapping using GB distributions.
We investigate the geometric properties of marginally trapped surfaces (surfaces which have null mean curvature vector) in the spaces of oriented geodesics of Euclidean 3-space and hyperbolic 3-space, endowed with their canonical neutral Kaehler structures. We prove that every rank one surface in these four manifolds i…
Eight different refinements of trapped surfaces are proposed, of three basic types, each intended as potential stability conditions. Minimal trapped surfaces are strictly minimal with respect to the dual expansion vector. Outer trapped surfaces have positivity of a certain curvature, related to surface gravity. Increas…
Study of marginally trapped surfaces in a perturbed Schwarzschild spacetime.
problem Understanding marginally trapped surfaces in perturbed Schwarzschild spacetime.
method Developed a method to study spacelike surfaces in a double null coordinate system.
result For every incoming null hypersurface nearly spherically symmetric, there exists a unique embedded marginally trapped surface.
The paper introduces canonical parameters for marginally trapped surfaces in Minkowski space.
problem Determining marginally trapped surfaces in Minkowski space.
method Introducing canonical parameters and proving existence and uniqueness theorems.
result Every marginally trapped surface is determined by three smooth functions.
Generic singularities found in spacetimes with weakly trapped submanifolds.
problem Existence of singularities in spacetimes with weakly trapped submanifolds.
method Using Whitney topologies and singularity theorems, the study shows genericity of singularities in spacetimes with weakly trapped submanifolds.
result Generic singularities are found in spacetimes with weakly trapped submanifolds.
Study improves curvature estimate for stable marginally outer trapped hypersurfaces with a free boundary.
problem Curvature estimate for stable marginally outer trapped hypersurfaces with a free boundary.
method Iteration argument based on uniform area bound.
result Improved curvature estimate for stable marginally outer trapped hypersurfaces.
Wariness affects poverty traps and equilibrium diversity in economic models.
problem The impact of wariness on poverty traps and equilibrium diversity in economic models.
method An overlapping generations model to explore the effects of wariness on poverty traps and equilibrium diversity.
result Wariness can amplify or mitigate the likelihood of poverty traps and can lead to multiple intertemporal equilibria.
We show that any vacuum initial data set containing a marginally outer trapped surface S and satisfying a "no KIDs" condition can be perturbed near S so that S becomes strictly outer trapped in the new vacuum initial data set. This, together with the results in [9], gives a precise sense in which generic initial data c…
Proves stable smooth minimal hypersurface for trapped region boundary in large dimensional manifolds.
problem Boundary stability of trapped region in large dimensional manifolds.
method Analyzes asymptotically Euclidean Riemannian manifolds of dimension at least 3.
result Boundary is a stable smooth minimal hypersurface except for a singular set of codimension at least 8.
A marginally trapped surface in the four-dimensional Minkowski space is a spacelike surface whose mean curvature vector is lightlike at each point. In the present paper we find all marginally trapped surfaces with pointwise 1-type Gauss map. We prove that a marginally trapped surface is of pointwise 1-type Gauss map if…
Proves two non-trapping obstacles coincide if scattering rays have similar travelling times or scattering length spectra.
problem Identifying non-trapping obstacles based on scattering properties.
method Proves two obstacles coincide if their scattering rays have similar travelling times or scattering length spectra under weak non-degeneracy conditions.
result Two non-trapping obstacles coincide if their scattering rays have similar travelling times or scattering length spectra.
This paper considers some fundamental questions concerning marginally trapped surfaces, or apparent horizons, in Cauchy data sets for the Einstein equation. An area estimate for outermost marginally trapped surfaces is proved. The proof makes use of an existence result for marginal surfaces, in the presence of barriers…
Study of trapped submanifolds in null hypersurfaces with curvature constraints.
problem Understanding trapped submanifolds in null hypersurfaces with curvature constraints.
method Analyzing null hypersurfaces with constant sectional curvature and proving properties of trapped submanifolds.
result Null trapping horizons cannot exist in null hypersurfaces with non-positive curvature.
Paper proves trapped surface formation for EMCSF system without symmetry assumptions.
problem Formation of trapped surfaces for the Einstein--Maxwell--charged scalar field system.
method Scale-critical trapped surface formation result established from past null infinity.
result Focusing of gravitational waves, concentration of electromagnetic fields, or condensation of scalar fields can lead to trapped surface formation.
Overview of marginally trapped surfaces in various spacetimes.
problem Understanding marginally trapped surfaces in different spacetimes.
method Differential geometric study of marginally trapped surfaces in Minkowski, de Sitter, anti-de Sitter, and Robertson-Walker spacetimes.
result General local descriptions and classifications of these surfaces.
No trapped surfaces can form under low-regularity bounds in certain spacetimes.
problem Existence of trapped surfaces in low regularity solutions to Einstein's equations.
method Analyzing the initial data in Besov B2,13/2 norm and extending to H3/2 smallness. result No trapped surfaces can exist initially when the Cauchy data are close to Minkowski spacetime data.
The concept of closed trapped surface is of paramount importance in General Relativity and other gravitational theories. However, it is a purely geometrical object. With the aim of bringing this concept to closer attention by the mathematical community, I introduce the generalized idea of trapped submanifold by using t…
Paper proves trapped surface formation for Einstein-Maxwell-charged scalar field system.
problem Formation of trapped surfaces in Einstein-Maxwell-charged scalar field system.
method Generalized Christodoulou's approach for spherical symmetry and improved for Minkowskian data.
result Improved bound on trapped surface formation for Minkowskian data.
Deep learning system speeds up wildlife species identification from camera trap images.
problem Manual review of camera trap images is slow and resource-intensive.
method Combines machine and human intelligence for active learning.
result Matches state-of-the-art accuracy with minimal manual labels.
In the present paper we provide new examples of marginally trapped surfaces and tubes in FLRW spacetimes by using a basic relation between these objects and CMC surfaces in 3-manifolds. We also provide a new method to construct marginally trapped surfaces in closed FLRW spacetimes, which is based on the classical Hopf …
We derive integral and sup-estimates for the curvature of stably marginally outer trapped surfaces in a sliced space-time. The estimates bound the shear of a marginally outer trapped surface in terms of the intrinsic and extrinsic curvature of a slice containing the surface. These estimates are well adapted to situatio…
New trapping effect found on degenerate horizons.
problem Understanding degenerate horizons in extreme black holes.
method Wave equation analysis in extremal Reissner-Nordstrom spacetime.
result Degenerate horizons exhibit a global trapping effect.
New system studies trapped light paths in Euclidean space.
problem Trapping of light paths in Euclidean space with negative refractive index.
method Introduces wind-tree tiling billiards system to study trajectories of rays in Euclidean space with rectangular obstacles.
result Almost every configuration of the system traps trajectories with initial vertical direction in an infinite strip.
The study generalizes Santalo's formula and shows stability of trapping sets in Riemannian manifolds.
problem Stability of trapping sets in Riemannian manifolds under smooth perturbations of obstacles.
method Generalization of Santalo's formula applied to billiard trajectories in the exterior of obstacles.
result The measure of the set of trapped points depends continuously on perturbations of the obstacle.
The paper studies marginally trapped submanifolds in Lorentzian manifolds under null energy condition.
problem Understanding marginally trapped submanifolds in Lorentzian manifolds.
method Analyzes properties of marginally trapped submanifolds in a Lorentzian manifold satisfying the null energy condition.
result Marginally trapped submanifolds have locally volume-maximizing properties in certain null hypersurfaces.
Study shows certain manifolds uniquely determined by X-ray data.
problem Determining manifolds from X-ray data.
method Injectivity of X-ray transform over symmetric solenoidal 2-tensors.
result Smooth compact manifolds with strictly convex boundary, no conjugate points, and hyperbolic trapped set are locally marked boundary rigid.
Study on trapped submanifolds in spacetimes, proving rigidity and non-existence results.
problem Rigidity and non-existence of trapped submanifolds in spacetimes.
method Analysis of parabolic spacelike submanifolds with causal mean curvature in orthogonally splitted and globally hyperbolic spacetimes.
result Non-existence of local minima or maxima of certain functions on submanifolds, leading to rigidity results.
Model shows how investment traps wealth across generations.
problem Existence of wealth traps between social strata.
method Developed a model linking investment and intergenerational wealth.
result Proved a `rat race' theorem showing investment traps wealth.
Scattering data on surfaces uniquely determine geodesic lengths.
problem Determining geodesic lengths on surfaces from scattering data.
method Analyzing scattering data on surfaces with specific conditions.
result Scattering data uniquely determine geodesic lengths on surfaces with no trapped geodesics.
New proof of trapped surface formation using signature for decay rates.
problem Trapped surface formation in gravitational collapse.
method Systematic approach with signature for decay rates, rescaling argument.
result Reproof and extension of a scale-critical theorem.
Study examines how insurance affects households prone to proportional losses, especially those near poverty.
problem Impact of insurance on households susceptible to proportional losses, focusing on poverty traps.
method Modelled proportional capital losses with insurance, derived closed formulae and non-local differential equations.
result New formulae and methods to calculate trapping probability, constraints on parameters to prevent certainty of trapping.
Study the intersection of a hyperplane with a lightcone in Minkowski spacetime.
problem Understanding the anisotropic criterion for formation of trapped surfaces in vacuum.
method Investigated the intrinsic and extrinsic geometry of the intersection of a hyperplane with a lightcone in Minkowski spacetime.
result Found that the intersection has constant positive, zero, or negative Gaussian curvature depending on the hyperplane's type.
Small deformations of marginally (outer) trapped surfaces are considered by using their stability operator. In the case of spherical symmetry, one can use these deformations on any marginally trapped round sphere to prove several interesting results. The concept of 'core' of a black hole is introduced: it is a minimal …
The paper examines the rigidity of marginally outer trapped 2-spheres in spacetime.
problem Stability and rigidity of marginally outer trapped 2-spheres in spacetime.
method Area inequality and splitting result for 3-dimensional initial data sets.
result Proves a splitting result for stable, weakly outermost marginally outer trapped 2-spheres achieving the area bound.
We solve the Plateau problem for marginally outer trapped surfaces in general Cauchy data sets. We employ the Perron method and tools from geometric measure theory to force and control a blow-up of Jang's equation. Substantial new geometric insights regarding the lower order properties of marginally outer trapped surfa…
New method shows trapped surfaces form in geodesic foliation.
problem Formation of trapped surfaces in Einstein vacuum equation.
method Geodesic foliation, non-integrable PT frame.
result Trapped surfaces form for Einstein vacuum equation.
New integrable systems for marginally trapped surfaces in 4D Lorentz-Minkowski space.
problem Constructing new representations for marginally trapped surfaces in L4. method Developed new Weierstrass-type representations to solve a linear PDE.
result Explicit examples of marginally trapped surfaces with non-vanishing mean curvature.
A marginally trapped surface in the four-dimensional Minkowski space is a spacelike surface whose mean curvature vector is lightlike at each point. We introduce meridian surfaces of parabolic type as one-parameter systems of meridians of a rotational hypersurface with lightlike axis in Minkowski 4-space and find their …
Galor's mysterious income growth rate is debunked, revealing data manipulation.
problem Mysterious sudden spurt in income per capita growth rate.
method Mathematical analysis of historical world economic growth data.
result The sudden spurt in income per capita growth rate is an artifact of data presentation.