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A locally-built, LLM-digested index of recent arXiv papers in quant finance, geometry/topology, and statistical ML — keyword search served straight from SQLite on this machine.

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48 results for lapse function

Lapse-supported life insurance exacerbates adverse selection risks.

problem Lapse-supported life insurance increases adverse selection costs.
method Modeling 'Term to 100' contracts and analyzing three methods of managing lapse surplus.
result Adverse selection losses can be almost unlimited under certain conditions.

Study rigidifies geometry of electrostatic systems with specific tensor properties.

problem Investigating rigidity in electrostatic systems with specific tensor properties.
method Analyzing static Einstein--Maxwell spacetimes with harmonic (anti-)self-dual Weyl tensor.
result Gradient of lapse function is an eigenvector of Ricci tensor and manifold is locally conformally flat.

In this article, existence results concerning temporal functions with additional properties on a globally hyperbolic manifold are obtained. These properties are certain bounds on geometric quantities as lapse and shift. The results are linked to completeness properties and the existence of closed isometric embeddings i…

2009-04-09abs ↗pdf ↗

New theorem proves uniqueness of Schwarzschild-de Sitter spacetime.

problem Proving the uniqueness of Schwarzschild-de Sitter spacetime.
method Developed new tools like reverse Lojasiewicz inequality and proved smoothness of maximum-set of lapse.
result Established a new uniqueness theorem for three-dimensional Schwarzschild-de Sitter metrics.

We consider four-dimensional vacuum spacetimes which admit a nonvanishing spacelike Killing field. The quotient with respect to the Killing action is a three-dimensional quotient spacetime (M,g)(M,g). We establish several results regarding maximal hypersurfaces (spacelike hypersurfaces of zero mean curvature) in such quot…

2016-03-02abs ↗pdf ↗

Lapse improves parameter servers by dynamically allocating parameters, achieving near-linear scaling.

problem Efficiently managing distributed training with reduced communication overhead.
method Integrate dynamic parameter allocation into parameter servers, proposing Lapse.
result Lapse provides near-linear scaling and can be orders of magnitude faster than existing parameter servers.

The classification of solutions of the static vacuum Einstein equations, on a given closed manifold or an asymptotically flat one, is a long-standing and much-studied problem. Solutions are characterized by a complete Riemannian nn-manifold (M,g)(M,g) and a positive function NN, called the lapse. We study this problem o…

2015-02-16abs ↗pdf ↗

Electrostatic systems with specific tensors are locally conformally flat.

problem Understanding the geometry of electrostatic systems with special tensors.
method Proving local conformal flatness for electrostatic manifolds with divergence-free Bach tensor.
result Three-dimensional electrostatic manifolds with divergence-free Bach tensor are locally conformally flat.

We characterize those spacetimes which admit a isometric (or conformal) embedding in some Lorentz-Minkowski space L^N. In particular, any globally hyperbolic spacetime can be isometrically embedded in L^N. This is proven by a result of its own interest: the construction of a smooth time function whose gradient is bound…

2008-12-23abs ↗pdf ↗

Let $\M_*=\cup_{t\in [t_0, t_*)} Σ_t$ be a part of vacuum globally hyperbolic space-time $(\bM, \bg)$, foliated by constant mean curvature hypersurfaces ΣtΣ_t with t0<t<0t_0<t_*<0. We show that the foliation can be extended beyond tt_* if the second fundamental form kk and the lapse function nn satisfy $$ \int_{t_0}^{t_…

2010-04-17abs ↗pdf ↗

We analyze (the harmonic map representation of) static solutions of the Einstein Equations in dimension three from the point of view of comparison geometry. We find simple monotonic quantities capturing sharply the influence of the Lapse function on the focussing of geodesics. This allows, in particular, a sharp estima…

2011-03-24abs ↗pdf ↗

We use an idea of Wang and Yau to give a new definition of quasi-local mass for a topological sphere in an initial date set. The new definition modifies Brown-York's definition by using certain spinor norm as lapse function. And it requires mean curvature of the topological sphere satisfies apparent horizon conditions,…

2006-03-02abs ↗pdf ↗

Study compares non-parametric models for predicting medical insurance reimbursement delays.

problem Estimating the time-lapse between medical insurance reimbursement.
method Comparative study of four non-parametric regression models (KNNs, SVMs, Decision Trees, Random Forests) using R-squared metric.
result Each model's performance varies with training data size, feature space, and hyperparameters.

In this paper we extend the local scalar curvature rigidity result in [6] to a small domain on general vacuum static spaces, which confirms the interesting dichotomy of local surjectivity and local rigidity about the scalar curvature in general in the light of the paper [10]. We obtain the local scalar curvature rigidi…

2014-12-04abs ↗pdf ↗

We present a new geometric approach to the study of static isolated general relativistic systems for which we suggest the name geometrostatics. After describing the setup, we introduce localized formulas for the ADM-mass and ADM/CMC-center of mass of geometrostatic systems. We then explain the pseudo-Newtonian characte…

2012-10-16abs ↗pdf ↗

The paper explores stable surfaces in Einstein-Maxwell theory, proving mass bounds and nonexistence results.

problem Exploring stable surfaces in static Einstein-Maxwell space-time.
method Using mean-stable surfaces theory to prove properties of lapse functions and mass bounds.
result Proves ADM mass is bounded by Hawking quasi-local mass.

We establish a black hole uniqueness theorem for Schwarzschild-de Sitter spacetime, also called Kottler spacetime, which satisfies Einstein's field equations of general relativity with positive cosmological constant. Our result concerns the class of static vacuum spacetimes with compact spacelike slices and regular max…

2010-09-05abs ↗pdf ↗

We show that local deformations, near closed subsets, of solutions to open partial differential relations can be extended to global deformations, provided all but the highest derivatives stay constant along the subset. The applicability of this general result is illustrated by a number of examples, dealing with convex …

2018-09-15abs ↗pdf ↗

We consider static spacetimes whose spatial part admits foliations with the extrinsic curvature tensor K_{ab}=0. There are two complementary cases when the gradient of the lapse function points 1) to the direction of foliation or 2) orthogonally to it. Case 1) gives generalization of metrics like Bertotti-Robinson or N…

2006-04-21abs ↗pdf ↗

Proposes a model to update industrial data predictions based on temporal changes.

problem Improving prediction accuracy in industrial data analytics by addressing changing conditions over time.
method Integrates similarity and loss functions to estimate and update prediction models adaptively.
result The data renewal model enhances prediction accuracy by identifying and updating model changes.

The paper classifies electrovacuum spaces in higher dimensions, proving several key results.

problem Classifying regular static black hole solutions of the static Einstein-Maxwell equations.
method Analytical proofs and geometric analysis of electrovacuum spaces.
result An n-dimensional locally conformally flat extremal electrovacuum space must be in the Majumdar-Papapetrou class.

Generative adversarial networks (GANs) are pow- erful generative models based on providing feed- back to a generative network via a discriminator network. However, the discriminator usually as- sesses individual samples. This prevents the dis- criminator from accessing global distributional statistics of generated samp…

2018-06-19abs ↗pdf ↗

Study on the geometry of Cotton gravity field equations.

problem Analyzing the geometry of Cotton gravity field equations.
method Describes the local structure of spatial Riemannian factors and provides sufficient conditions for reduction to φ\varphi-static perfect fluid space-time.
result Provides sufficient conditions for a C-φ\varphi-PF to reduce to a φ\varphi-SPFST.

We establish a uniform estimate for the injectivity radius of the past null cone of a point in a general Lorentzian manifold foliated by spacelike hypersurfaces and satisfying an upper curvature bound. Precisely, our main assumptions are, on one hand, upper bounds on the null curvature of the spacetime and the lapse fu…

2010-08-30abs ↗pdf ↗

New relation found between ADM mass and generalized Komar energy for dynamical spacetimes.

problem Finding equality between ADM mass and Komar energy in dynamical spacetimes.
method Constructing a generalized Komar energy from the normal evolution vector and proving equality under specific conditions.
result Equality between ADM mass and generalized Komar energy for dynamical asymptotically-flat spacetimes.

Perelman's Ricci flow emerges in quantum gravity, linking math and physics.

problem Understanding Perelman's Ricci flow equations in quantum gravity.
method Mapping Perelman's Ricci flow equations to localization equations in topological quantum gravity.
result Perelman's dilaton and fixed volume condition emerge dynamically.

Solves Einstein vacuum equations gluing problem for close Minkowski data.

problem Solving the characteristic gluing problem for Einstein vacuum equations.
method Derived infinite-dimensional and 10-dimensional gauge-dependent and gauge-invariant charges; constructed null lapse function and conformal geometry.
result Obstructions to gluing problem are gauge-dependent charges, modulo gauge-invariant charges.

This paper modifies the Ait-Sahalia model to better describe interest rate behaviors.

problem Inadequate specifications of the original Ait-Sahalia model to explain various interest rate phenomena.
method Proposes a modified hybrid Poisson-jump Ait-Sahalia model and uses truncated EM techniques for numerical approximation.
result Validates the modified model using Monte Carlo simulations for bond and barrier option payoffs.