Research
On-device research index

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.

168,742 papers · 148 categories

Trend · papers per month

152303455606 · Jun 202019922001200920172026
48 results for conjugate time

Motivated by the study of linear quadratic optimal control problems, we consider a dynamical system with a constant, quadratic Hamiltonian, and we characterize the number of conjugate times in terms of the spectrum of the Hamiltonian vector field H\vec{H}. We prove the following dichotomy: the number of conjugate time…

2013-11-08abs ↗pdf ↗

Study geodesics on Grushin spaces, proving upper bounds on conjugate times.

problem Classify geodesics on higher-dimensional Grushin spaces.
method Solve Hamilton's equations using calculus of generalized trigonometric functions, analyze symmetries, and use density arguments.
result Prove a conjectured cut time provides an upper bound on conjugate times.

Geodesic flows on certain surfaces are shown to be semi-conjugate to expansive flows.

problem Understanding geodesic flows on compact surfaces without conjugate points.
method Time-preserving semi-conjugation to a continuous expansive flow.
result Geodesic flows on compact surfaces without conjugate points of genus > 1 have a unique measure of maximal entropy.

Study of Lévy flights on Zoll surfaces, revealing geometric information.

problem Understanding the mean first capture time of Lévy flights on Zoll surfaces.
method Analysis of geodesic Lévy processes on Zoll surfaces, focusing on the first correction term.
result The first correction term encodes geometric information, specifically the degree of the conjugate point.

The study identifies conjugate and cut points in ideal fluid motion configurations.

problem Understanding stability and re-convergence of fluid configurations.
method Existence and non-existence of conjugate points in specific fluid configurations, using geometric and physical analysis.
result Existence of conjugate points in Kolmogorov flows and non-existence in Arnold steady states.

Study geodesics and shortest arcs on Lie groups with specific metrics.

problem Characterize geodesics and shortest arcs in sub-Riemannian metrics on Lie groups.
method Investigated left-invariant sub-Riemannian metrics on SU(1,1)imesRSU(1,1) imes\mathbb{R} and SO0(2,1)imesRSO_0(2,1) imes\mathbb{R}.
result Found geodesics, shortest arcs, cut loci, and conjugate loci.

In this paper, we introduce the (co)homology group of a multiple conjugation biquandle. It is the (co)homology group of the prismatic chain complex, which is related to the homology of foams introduced by J. S. Carter, modulo a certain subchain complex. We construct invariants for S1S^1-oriented handlebody-links using …

2018-01-22abs ↗pdf ↗

The paper studies conjugate points on Lie groups with specific metrics.

problem Existence and properties of conjugate points on Lie groups with left-invariant metrics.
method Using reformulated index form in terms of adjoint action, the paper proves sufficient conditions for conjugate points and provides bounds and criteria.
result All geodesics in compact semisimple Lie groups have conjugate points, with upper and lower bounds on conjugate times.

In this paper we study smooth orientation-preserving free actions of the cyclic group Z/m\mathbb Z/m on a class of (n1)(n-1)-connected 2n2n-manifolds, g(Sn×Sn)Σ\sharp g (S^n \times S^n)\sharp Σ, where ΣΣ is a homotopy 2n2n-sphere. When n=2n=2 we obtain a classification up to topological conjugation. When n=3n=3 we obtain a classi…

2019-11-29abs ↗pdf ↗

Let (M,g(t))(M,g(t)), 0tT0\le t\le T, Mφ\partial M\neφ, be a compact nn-dimensional manifold, n2n\ge 2, with metric g(t)g(t) evolving by the Ricci flow such that the second fundamental form of M\partial M with respect to the unit outward normal of M\partial M is uniformly bounded below on M×[0,T]\partial M\times [0,T]. We will pr…

2008-01-23abs ↗pdf ↗

Improved Gaussian process regression with tighter log marginal likelihood bounds.

problem Improving predictive performance in Gaussian process regression models.
method Lower bound on log marginal likelihood using conjugate gradients.
result Improved predictive performance compared to other conjugate gradient based approaches.

Study dispersive estimates for Schrödinger and wave equations on a cone with specific metric.

problem Pointwise decay estimates for Schrödinger and wave equations on a product cone.
method Modified Hadamard parametrix on YY with ε>πε > π to prove dispersive estimates.
result Threshold of conjugate radius ε>πε > π for pointwise dispersive estimates.

The paper tackles efficient computation of optimal transport by approximating conjugates with amortized optimization.

problem Efficient computation of convex conjugates in optimal transport is challenging and limits the quality of transport maps.
method The approach combines amortized approximations of conjugates with a fine-tuning solver to improve transport map quality.
result The method significantly improves the quality of transport maps for the Wasserstein-2 benchmark and models many 2D couplings and flows.

Quotients Y=X/conjY=X/conj by the complex conjugation conjXXconj\: X\to X for complex surfaces XX defined over R\R tend to be completely decomposable when they are simply connected, i.e., split into connected sums $\#_n CP^2\#_m\barCP^2$ if w2(Y)0w_2(Y)\ne0, or into #n(S2×S2)\#_n(S^2\times S^2) if w2(Y)=0w_2(Y)=0. The author proves this prope…

1995-12-11abs ↗pdf ↗

Develops multi-modal neural network models for improved prediction and uncertainty quantification.

problem Improving prediction accuracy and uncertainty quantification for multi-modal data.
method Multi-modal Bayesian neural network models with conjugate last-layer estimation using SVI.
result Improved prediction accuracy and uncertainty quantification compared to uni-modal models.

A conjugate Bayesian method detects change points in Hawkes processes efficiently.

problem Non-conjugacy between Hawkes process likelihood and prior causes inefficiency in change point detection.
method Data augmentation to propose a conjugate Bayesian two-step change point detection method.
result The conjugate method is more accurate and efficient than non-conjugate methods.

New method speeds up inference for non-conjugate Gaussian processes.

problem Inference for non-conjugate Gaussian processes is slow and unreliable.
method Automated augmented conjugate inference method that constructs auxiliary variables to make the model conditionally conjugate.
result Our method is up to two orders of magnitude faster and more robust than existing methods.

In this paper, we classify smooth 5-manifolds with fundamental group isomorphic to $\z/2$ and universal cover diffeomorphic to S2×S3S^2 \times S^3. This gives a classification of smooth free involutions on S2×S3S^2 \times S^3 up to conjugation.

2009-07-16abs ↗pdf ↗

Geometric focusing affects dispersive estimates for Schrödinger and wave equations.

problem Long-time decay rate in dispersive estimates for Schrödinger and wave equations on non-trapping asymptotically conic manifolds and exact metric cones.
method Classifying the long-time decay rate in dispersive estimates for the Schrödinger and wave equations on non-trapping asymptotically conic manifolds and exact metric cones in terms of the intensity of geometric focusing.
result Each multiplicity of conjugate points within distance π on Y = ∂X0 leads to a |t|1/2-loss in the long-time decay order and a half-order shift in the regularity index in the dispersive estimate for the Schrödinger equation.

We introduce a multiple conjugation biquandle, and show that it is the universal algebra to define a semi-arc coloring invariant for handlebody-links. A multiple conjugation biquandle is a generalization of a multiple conjugation quandle. We extend the notion of nn-parallel biquandle operations for any integer nn, an…

2017-02-05abs ↗pdf ↗

We show that the standard stochastic gradient decent (SGD) algorithm is guaranteed to learn, in polynomial time, a function that is competitive with the best function in the conjugate kernel space of the network, as defined in Daniely, Frostig and Singer. The result holds for log-depth networks from a rich family of ar…

2017-02-27abs ↗pdf ↗

The paper studies Jacobi fields and conjugate points in projective sprays.

problem Investigating Jacobi fields and conjugate points in projective sprays.
method Proved that conjugate points are preserved under projective changes and established conditions for the existence of conjugate points.
result Conditions for the existence of conjugate points in projectively deformed sprays.

Paper describes how to extend multiple conjugation quandles using maps.

problem Understanding affine extensions of multiple conjugation quandles.
method Introduces augmented MCQ Alexander pairs for affine extensions.
result Affine extensions of multiple conjugation quandles can be described by quadruples of maps.

For a surface group, a new bound is given for conjugator length function.

problem Finding an explicit bound for the conjugator length function of a surface group.
method Detailed analysis of conjugation reductions.
result An explicit bound n1CL(2n)n+8g1n-1 \leq \mathrm{CL}(2n) \leq n+8g-1 for the conjugator length function of a surface group.

The study examines Hopfian properties of conjugation quandles and their underlying groups.

problem Understanding the relationship between Hopfian properties of conjugation quandles and their underlying groups.
method Examined Hopfian and residual finiteness properties of conjugation quandles of specific groups.
result Conjugation quandles of Baumslag-Solitar groups are infinitely generated and not necessarily Hopfian.

Upper bound for conjugate radius in open manifolds with scalar curvature and spectrum constraints.

problem Bounding the conjugate radius of open manifolds with specific curvature and spectrum conditions.
method Established an upper bound using scalar curvature and bottom-of-spectrum constraints.
result For certain conditions, the conjugate radius is no more than π.

An embedding of the m-times punctured disc into the n-times punctured disc, for n>m, yields an embedding of the braid group on m strands B_m into the braid group on n strands B_n, called a geometric embedding. The main example consists of adding n-m trivial strands to the right of each braid on m strands. We show that …

2013-08-06abs ↗pdf ↗

The questions when two Morse function on closed manifolds are conjugated is investigated. Using the handle decompositions of manifolds the condition of conjugation is formulated. For each Morse function on 3-manifold the ordered generalized Heegaard diagram is built. The criteria of Morse function conjugation are given…

1998-12-28abs ↗pdf ↗

Paper finds new criteria for conjugate points in fluid flows.

problem Finding conjugate points in steady 2D Euler flows.
method Develops a new sufficient criterion for conjugate points, applies to any rotational cell, and uses a general construction of steady fluid surfaces.
result Improves on existing criteria and captures all known conjugate points in rotational cells.

Study analyzes Lévy process structure on manifolds with conjugate points.

problem Microlocal analysis of Lévy processes on manifolds with conjugate points.
method Microlocal analysis, pseudodifferential operators, Fourier integral operators.
result Generator can be expressed as sum of pseudodifferential and Fourier integral operators.

We study the geodesic X-ray transform XX on compact Riemannian surfaces with conjugate points. Regardless of the type of the conjugate points, we show that we cannot recover the singularities and therefore, this transform is always unstable (ill-posed). We describe the microlocal kernel of XX and relate it to the con…

2014-02-22abs ↗pdf ↗

We describe the sample paths of the stochastic field F=Ft(v,x,q)F = F_t(v,x,q) of aggregate utilities parameterized by Pareto weights vv and total cash amounts xx and stocks' quantities qq in an economy. We also describe the sample paths of the stochastic field G=Gt(u,y,q)G = G_t(u,y,q), which is conjugate to FF with respect to the …

2013-10-28abs ↗pdf ↗