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arXiv research

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.

169,341 papers · 148 categories

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22446587 · May 202619922001200920182026
48 results for uniformly contracting

Groups can embed uniformly but not act properly on contractible manifolds.

problem Understanding the difference between group actions and embeddings on contractible manifolds.
method Analyzing the relationship between group actions and uniform embeddings on contractible manifolds.
result k-fold products of specific groups do not act on contractible manifolds.

The paper proves scalar curvature decay for uniformly contractible manifolds with finite asymptotic dimension.

problem Proving decay of scalar curvature for uniformly contractible manifolds with finite asymptotic dimension.
method Using index pairing between Dirac operators and compactly supported vector bundles with Lipschitz control, and Lipschitz control for topological K-theory of finite dimensional simplicial complexes.
result The scalar curvature decays to zero at a rate depending only on the contractibility radius and the diameter control of the asymptotic dimension.

We show that a space with a finite asymptotic dimension is embeddable in a non-positively curved manifold. Then we prove that if a uniformly contractible manifold X is uniformly embeddable in Rn\R^n or non-positively curved n-dimensional simply connected manifold then X×RnX\times\R^n is integrally hyperspherical. If a un…

1999-12-08abs ↗pdf ↗

We consider compact convex hypersurfaces contracting by functions of their curvature. Under the mean curvature flow, uniformly convex smooth initial hypersurfaces evolve to remain smooth and uniformly convex, and contract to points after finite time. The same holds if the initial data is only weakly convex or non-smoot…

2011-04-05abs ↗pdf ↗

Uniformly extend maps on Hadamard manifolds with curvature constraints.

problem Extending maps on Hadamard manifolds with curvature constraints.
method Proving uniform extension for contracting maps on Hadamard manifolds with curvature bounds.
result Uniform Lipschitz extension achieved for contracting maps on Hadamard manifolds with curvature constraints.

This paper examines limits of Riemannian 2-manifolds with bounded curvature.

problem Understanding the limits of Riemannian 2-manifolds with bounded curvature.
method Uniform semi-locally 1-connected sequences of closed connected Riemannian 2-manifolds with bounded total absolute curvature.
result Description of Gromov-Hausdorff limits of the sequences.

The paper shows how convex hypersurfaces contract under a specific curvature flow.

problem Understanding the behavior of convex hypersurfaces under curvature-driven contraction.
method Proves convergence of convex hypersurfaces in Rn+1{\mathbb R}^{n+1} to a self-similar solution under a flow by powers of the Gauss curvature.
result The limit of the flow is a smooth, uniformly convex self-similar solution, and under central symmetry, it is the round sphere.

No 5D aspherical manifolds can have uniformly positive scalar curvature.

problem Proving the non-existence of metrics with positive scalar curvature on certain 5D manifolds.
method Uniform acyclicity and toric symmetrization of stable μ-bubbles.
result Compact aspherical 5-manifolds cannot have metrics with uniformly positive scalar curvature.

Curvature conditions distinguish Euclidean space and disks in contractible manifolds.

problem Distinguish Euclidean space and disks among contractible manifolds.
method Investigate curvature conditions on open and compact contractible manifolds with boundary.
result Stronger curvature conditions can distinguish disks from Euclidean spaces.

Study finds topological restrictions on 4-manifolds with uniformly positive scalar curvature.

problem Understanding which 4-manifolds can have metrics with uniformly positive scalar curvature.
method Topological obstructions and metric constructions on specific 4-manifolds.
result Existence of uncountably many exotic R4\mathbb{R}^4's without such metrics and topological uniqueness of certain metrics.

The paper analyzes game theory in convertible contracts during liquidity events.

problem Optimizing payments in convertible contracts during liquidity events.
method Defined a general model for games, showed non-existence of pure strategy Nash equilibria, developed algorithms for computing equilibria.
result Optimum pure strategy Nash equilibria exist when all contracts are of the same type (SAFE).

Nonspin manifolds can't have uniformly positive scalar curvature.

problem Proving nonexistence of uniformly positive scalar curvature metrics on nonspin manifolds.
method Using Schoen-Yau's minimal hypersurface results and properties of maps to product spaces.
result Enlargeable metrics on nonspin manifolds cannot have uniformly positive scalar curvature.

We construct a compact metric space that has any other compact metric space as a tangent, with respect to the Gromov-Hausdorff distance, at all points. Furthermore, we give examples of compact sets in the Euclidean unit cube, that have almost any other compact set of the cube as a tangent at all points or just in a den…

2014-06-30abs ↗pdf ↗

The paper proves the Generalized Smale Conjecture and contractibility of moduli spaces.

problem Proving the Generalized Smale Conjecture and contractibility of moduli spaces of constant curvature.
method Ricci flow through singularities to prove contractibility and homotopy equivalence.
result The inclusion of isometries into diffeomorphisms is a homotopy equivalence for constant curvature metrics.

The paper studies circle packings using renormalization and subdivision rules.

problem Characterizing and proving properties of circle packings with specific subdivision rules.
method Iterations of skinning maps on Teichmüller spaces, renormalization theory, subdivision rules.
result Uniformly contracting renormalization operator and geometric inflexibility of circle packings.

Proposes a new generalization bound for Bayesian deep nets without strict assumptions.

problem Lack of generalization bounds for Bayesian deep nets without strict assumptions.
method Exploits contractivity of Log-Sobolev inequalities to add a loss-gradient norm term to the generalization bound.
result Introduces a new generalization bound for Bayesian deep nets that avoids strict assumptions.

Transformer pretraining yields strong EB performance without explicit adaptation.

problem Empirical Bayes problems with unknown test distributions.
method Indirect analysis of pretrained transformer's performance under universal priors.
result Near-optimal regret bound of O~(1n)\widetilde{O}(\frac{1}{n}) for arbitrary test distributions.

We prove that the restricted holonomy group of a complete smooth solution to the Ricci flow of uniformly bounded curvature cannot spontaneously contract in finite time; it follows, then, from an earlier result of Hamilton that the holonomy group is exactly preserved by the equation. In particular, a solution to the Ric…

2011-05-18abs ↗pdf ↗

This paper proves properties of uniformly hyperbolic sets and constructs Markov partitions.

problem Establishing properties of uniformly hyperbolic sets and constructing Markov partitions.
method Backward graph transform, spectral decomposition, shadowing lemma, Markov partitions construction.
result Explicit bounds and Hölder continuity for the coding map.

We develop some basic Lipschitz homotopy technique and apply it to manifolds with finite asymptotic dimension. In particular we show that the Higson compactification of a uniformly contractible manifold is mod pp acyclic in the finite dimensional case. Then we give an alternative proof of the Higher Signature Novikov …

2001-02-19abs ↗pdf ↗

Three themes of general topology: quotient spaces; absolute retracts; and inverse limits - are reapproached here in the setting of metrizable uniform spaces, with an eye to applications in geometric and algebraic topology. The results include: 1) If f: A -> Y is a uniformly continuous map, where X and Y are metric spac…

2011-06-16abs ↗pdf ↗

Making use of the Kerr theorem for shear-free null congruences and of Newman's representation for a virtual charge ``moving'' in complex space-time, we obtain an axisymmetric time-dependent generalization of the Kerr congruence, with a singular ring uniformly contracting to a point and expanding then to infinity. Elect…

2009-08-07abs ↗pdf ↗

Study on singularities of solutions to Hamilton-Jacobi equations on manifolds.

problem Characterizing singularities of solutions to time-dependent Hamilton-Jacobi equations.
method Uniformly continuous viscosity solutions, Tonelli Hamiltonians, homotopy theory.
result The set of points where solutions are not differentiable is locally contractible.

Study of Brown--York mass for four-dimensional asymptotically flat manifolds.

problem Calculating mass for hypersurfaces in four-dimensional asymptotically flat manifolds.
method Intrinsic definition of mean curvature, expansion analysis for large uniformly convex hypersurfaces.
result Shape-dependent correction to ADM mass for nearly round surfaces vanishes under certain conditions.

Improved stochastic Halpern iteration for fixed-point approximation in normed spaces.

problem Approximating fixed-points of nonexpansive and contractive operators in normed finite-dimensional spaces.
method Stochastic Halpern iteration with minibatch, analyzing oracle complexity.
result Improved oracle complexity for nonexpansive operators, with a lower bound of Ω(ε3)Ω(\varepsilon^{-3}).

Quasi-isometries in horospherical products are close to product maps.

problem Understanding the rigidity of quasi-isometries in specific geometric spaces.
method Proving quasi-isometries are uniformly close to product maps in horospherical products of hyperbolic spaces.
result Quasi-isometries of horospherical products of hyperbolic spaces are geometrically rigid.

GCAO improves clustering of high-dimensional data by grouping low-density boundary points.

problem Stability and accuracy of clustering in high-dimensional, non-uniform data.
method Group-level optimization with gravitational attraction and optimization.
result GCAO outperforms 11 clustering methods on multiple datasets.

In this article, we introduce the notion of a functor on coarse spaces being coarsely excisive- a coarse analogue of the notion of a functor on topological spaces being excisive. Further, taking cones, a coarsely excisive functor yields a topologically excisive functor, and for coarse topological spaces there is an ass…

2010-02-24abs ↗pdf ↗

Hypothesis testing in singular models is fundamentally about identifiable vs. non-identifiable parameters.

problem Testing in singular models is inherently problematic due to non-identifiability and degeneracy of Fisher information.
method Formalized the overlap obstruction and showed that hypotheses over non-identifiable parameters are untestable, while those over identifiable parameters reduce to classical testing.
result Hypotheses over non-identifiable parameters are untestable, while those over identifiable parameters reduce to classical testing.

The paper proves convergence of certain curvature flows to the origin.

problem Analyzing the convergence of specific curvature flows in Euclidean space.
method Examining fully nonlinear contracting curvature flows with given normal speeds.
result The flows converge exponentially to a sphere centered at the origin after rescaling.

Paper studies long-run risk optimization with dyadic impulses for unbounded processes.

problem Long-run risk optimization problem with unbounded and non-uniformly ergodic processes.
method Adapting weight norm approach, combining geometric drift and local minorization property.
result Existence of solution to Bellman equation for risk-averse parameters.

The paper explores coalescent contractions in contractible spaces, providing criteria and examples.

problem Existence and absence of coalescent contractions in contractible spaces.
method Analysis of contractible finite simplicial complexes and criteria for coalescent contractions.
result Criteria for contractible finite simplicial complexes that ensure no coalescent contractions.

New set type with no uniformly perfect subsets.

problem Understanding compact sets without uniformly perfect subsets.
method Introduced hereditarily non uniformly perfect sets and compared them with other types of sets.
result Example of a compact set with Hausdorff dimension 2 and positive logarithmic capacity is hereditarily non uniformly perfect.

In an online contract selection problem there is a seller which offers a set of contracts to sequentially arriving buyers whose types are drawn from an unknown distribution. If there exists a profitable contract for the buyer in the offered set, i.e., a contract with payoff higher than the payoff of not accepting any c…

2013-05-15abs ↗pdf ↗

Optimal execution strategy for merger & acquisition contracts with price impact.

problem Optimal execution and pricing of financial derivatives in M&A deals.
method Indifference utility arguments, considering linear and nonlinear contracts.
result Linear contracts are more expensive and vulnerable to manipulation.