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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.

168,657 papers · 148 categories

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82163245326 · Jun 202019922001200920172026
48 results for transnormal systems

Paper classifies transnormal systems on compact 3-manifolds.

problem Classifying transnormal systems on compact 3-manifolds.
method Establishing detailed relationships between transnormal systems of different types and their behaviors under covering maps.
result Ambient manifolds must be locally isometric to one of six standard geometries up to equivalence for CPC transnormal systems.

The abstract discusses the equivalence of transnormal and isoparametric functions on compact manifolds.

problem The existence of transnormal and isoparametric functions on compact manifolds.
method Exploring embedded transnormal systems and showing the existence of transnormal functions on Riemannian manifolds.
result Compact manifolds with transnormal functions also have isoparametric functions, and vice versa.

Study on transnormal functions and their level sets on Finsler manifolds.

problem Understanding transnormal functions and their geometric properties on Finsler manifolds.
method Proving smoothness of focal varieties and regular level sets of transnormal functions.
result Focal varieties of a C2 transnormal function are smooth submanifolds and regular level sets are tubes over these varieties.

Among a family of 2-parameter left invariant metrics on Sp(2), we determine which have nonnegative sectional curvatures and which are Einstein. On the quotiente N~11=(Sp(2)×S4)/S3\widetilde{N}^{11}=(Sp(2)\times S^4)/S^3, we construct a homogeneous isoparametric foliation with isoparametric hypersurfaces diffeomorphic to Sp(2). Further…

2019-12-05abs ↗pdf ↗

In this note we discuss a few properties of transnormal Finsler functions, i.e., the natural generalization of distance functions and isoparametric Finsler functions. In particular, we prove that critical level sets of an analytic transnormal function are submanifolds, and the partition of MM into level sets is a Fins…

2018-07-23abs ↗pdf ↗

The study extends Obata's theorem and classifies Finsler manifolds with transnormal functions.

problem Classifying Finsler manifolds based on geometric properties.
method Extending Obata's theorem and using a second order differential equation.
result Complete Finsler manifolds of positive constant flag curvature are homeomorphic to spheres.

The paper proves isoparametric functions on Finsler space forms under specific conditions.

problem Understanding isoparametric functions in Finsler space forms.
method Proving transnormal functions as isoparametric functions and constructing global and local isoparametric functions using the distance function.
result Generalization of Theorem B to Finsler space forms.

The first part of the paper is to improve the fundamental theory of isoparametric functions on general Riemannian manifolds. Next we focus our attention on exotic spheres, especially on "exotic" 4-spheres (if exist) and the Gromoll-Meyer sphere. In particular, as one of main results we prove: there exists no properly t…

2010-03-01abs ↗pdf ↗

In this paper, we introduce isoparametric functions and isoparametric hypersurfaces in Finsler manifolds and give the necessary and sufficient conditions for a transnormal function to be isoparametric. We then prove that hyperplanes, Minkowski hyperspheres and FF^*-Minkowski cylinders in a Minkowski space with BHBH-vo…

2015-07-15abs ↗pdf ↗

Given a vector field XX in a Riemannian manifold, a hypersurface is said to have a canonical principal direction relative to XX if the projection of XX onto the tangent space of the hypersurface gives a principal direction. We give different ways for building these hypersurfaces, as well as a number of useful charac…

2011-10-10abs ↗pdf ↗

In this paper we study singular riemannian foliations that have sections,i.e., totally geodesic complete immersed submanifolds that meet each leaf orthogonally and whose dimensions are the codimensions of the regular leaves. We prove here that the restriction of the foliation to a slice of a leaf is diffeomorphic to an…

2003-11-25abs ↗pdf ↗

In this paper, I study the isoparametric hypersurfaces in a Randers sphere (Sn,F)(S^n,F) of constant flag curvature, with the navigation datum (h,W)(h,W). I prove that an isoparametric hypersurface MM for the standard round sphere (Sn,h)(S^n,h) which is tangent to WW remains isoparametric for (Sn,F)(S^n,F) after the navigation proc…

2017-04-22abs ↗pdf ↗

Overview of integrable systems with symmetries, focusing on toric and semitoric systems.

problem Classifying and understanding integrable systems with symmetries.
method Using decorated polygons and controlled bifurcations in one-parameter families of systems.
result Construction of explicit semitoric systems with prescribed invariants.

Learning to control linear systems is statistically hard, especially for underactuated systems.

problem Statistical difficulty of learning to control linear systems, especially underactuated ones.
method Utilized minimax lower bounds and structural assumptions to prove learning complexity can be exponential.
result Learning complexity can be at most exponential with the controllability index of the system.

Discrete-time systems can be characterized by simple flat coordinates and their shifts.

problem Characterizing flatness of discrete-time systems.
method Developed a map from flat coordinates and their shifts to system state and input, fulfilling system equations identically.
result Derived necessary conditions for a system to be flat, without requiring differential geometry methods.

The paper explores when linear system identification is hard or easy, especially for under-actuated systems.

problem Statistical hardness of learning linear systems, especially under-actuated or under-excited systems.
method Using tools from minimax theory and recent statistical tools for finite sample analysis of system identification.
result The controllability index of linear systems affects the sample complexity of identification, making some systems hard to learn.

This paper improves system identification by reducing sample complexity for high-dimensional linear dynamical systems.

problem High sample complexity for learning partially observed linear dynamical systems in high dimensions.
method Introduces an 1\ell_1-regularized estimation method that reduces sample complexity from linear to logarithmic with system dimension.
result Markov parameters can be learned with logarithmic number of samples relative to system dimension, improving sample complexity.

In integrable hydrodynamic systems, coordinates exist where generators and symmetries are simple.

problem Existence of Riemannian invariants for integrable systems of hydrodynamic type.
method Finding coordinates where the generator and all symmetries are diagonal.
result In integrable hydrodynamic systems, there exist coordinates where the generator and all symmetries are diagonal.

This paper studies nonholonomic constraints in Hamiltonian systems, deriving equations and theorems.

problem Analyzing nonholonomic constraints in Hamiltonian systems.
method Deriving distributional RCH systems, geometric constraint conditions, and Hamilton-Jacobi theorems.
result Derives precise geometric constraint conditions and Hamilton-Jacobi theorems for nonholonomic systems.

This paper considers control systems defined on Lie algebroids. After deriving basic controllability tests for general control systems, we specialize our discussion to the class of mechanical control systems on Lie algebroids. This class of systems includes mechanical systems subject to holonomic and nonholonomic const…

2004-02-26abs ↗pdf ↗

Systemic risk refers to the risk that the financial system is susceptible to failures due to the characteristics of the system itself. The tremendous cost of systemic risk requires the design and implementation of tools for the efficient macroprudential regulation of financial institutions. The current paper proposes a…

2015-02-27abs ↗pdf ↗

The paper develops methods to derive mixed superposition rules for Lie systems and applies them to various physical systems.

problem Finding general solutions for Lie systems.
method Develops mixed superposition rules for Lie systems with imprimitive Lie algebras and semidirect sums.
result Extends coalgebra method to Lie systems of partial differential equations.

Paper develops reduction theory for controlled Lagrangian systems with symmetry and momentum map.

problem Reduction of controlled Lagrangian systems with symmetry and momentum map.
method Using Legendre transformation and Euler-Lagrange vector field, the paper extends symmetric reduction theory.
result Established regular reduction theory for RCL systems with symmetry and momentum map.

The paper studies connections in superintegrable systems, revealing geometric insights.

problem Understanding non- and semi-degenerate superintegrable systems.
method Analyzes two torsion-free connections associated with superintegrable systems.
result Semi-degenerate secondary structure tensor is the Ricci curvature of a natural torsion-free connection.

This paper proposes a system-agnostic policy for dynamic scheduling.

problem Dynamic scheduling in changing systems is challenging due to system-specific optimal policies.
method Descriptive policy that learns a system-agnostic scheduling principle.
result System-agnostic meta-learning enables adaptation to unseen system characteristics.

New Lie systems derived from Goursat distributions with applications to differential equations.

problem Analyzing Lie systems associated with Goursat distributions and their applications.
method Analyzing bracket-generating distributions and their relation to Lie systems, focusing on reductions and reconstructions.
result Lie systems associated with Goursat distributions can be reduced and solutions reconstructed from reduced systems.

Study integrable discretizations of cyclic systems with circular coordinate lines.

problem Integrable discretizations of 3D cyclic systems with circular coordinate lines.
method Investigate circle congruences and flat connections in the context of discrete cyclic systems.
result Characterization of circle congruences and existence of certain flat connections.

A new chaotic financial system is proposed by considering ethics involvement in a four-dimensional financial system with market confidence. A five-dimensional conformable derivative financial system is presented by introducing conformable fractional calculus to the integer-order system. A discretization scheme is propo…

2019-03-11abs ↗pdf ↗

A distributed system identification method for LTI systems using reverse experience replay.

problem Online system identification of LTI systems over multi-agent networks.
method DSGD-RER, a distributed variant of SGD-RER with backward updates.
result The estimation error decreases as the network size grows.

This work extends reduction processes for nonholonomic discrete mechanical systems.

problem Nonholonomic discrete mechanical systems and their reductions.
method Introduces a category LDPdLDP_d of discrete-time dynamical systems and a two-stage reduction process.
result Two-stage reduction process produces systems isomorphic to one-stage reduction.

Proposes a RL method using simulators for stabilizing uncertain systems.

problem Limited experiences and potential dangerous actions during RL learning of real systems.
method Two-stage approach: virtual systems for Q-function learning, real system interactions for final policy.
result Proposed method improves RL performance in uncertain discrete-time systems.