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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.

168,694 papers · 148 categories

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4182122163 · May 202619922001200920172026
48 results for logarithmic diffusion

The paper studies a 1D diffusion equation with nonlinear Robin boundary conditions and finds conditions for global and finite time blow-up or blow-down.

problem Investigating the behavior of solutions to a specific diffusion equation with nonlinear Robin boundary conditions.
method Analyzing the Ricci flow on a cylinder and applying it to the diffusion equation.
result Conditions for global and finite time blow-up or blow-down of solutions.

Through the main example of the Ornstein-Uhlenbeck semigroup, the Bakry-Emery criterion is presented as a main tool to get functional inequalities as Poincaré or logarithmic Sobolev inequalities. Moreover an alternative method using the optimal mass transportation, is also given to obtain the logarithmic Sobolev inequa…

2010-09-17abs ↗pdf ↗

Study of diffusion annealed Langevin dynamics for generative models.

problem Theoretical efficiency of score-based diffusion processes.
method Rigorous construction and analysis of diffusion processes with Poincaré and logarithmic Sobolev inequalities.
result Improvement in efficiency of diffusion processes through Poincaré and logarithmic Sobolev inequalities.

First, classes of Markov processes that scale exactly with a Hurst exponent H are derived in closed form. A special case of one class is the Tsallis density, advertised elsewhere as nonlinear diffusion or diffusion with nonlinear feedback. But the Tsallis model is only one of a very large class of linear diffusion with…

2006-06-05abs ↗pdf ↗

Uniform heat kernel and diffusion bridge asymptotics for sub-Riemannian geometry.

problem Analyzing sub-Riemannian heat kernels and their derivatives on incomplete manifolds.
method Localized asymptotic analysis, focusing on minimizing geodesics and the non-abnormal cut locus.
result Uniform bounds and expansions for heat kernels and their derivatives on compacts, including the diffusion bridge measure.

We show that our generalization of the Black-Scholes partial differential equation (pde) for nontrivial diffusion coefficients is equivalent to a Martingale in the risk neutral discounted stock price. Previously, this was proven for the case of the Gaussian logarithmic returns model by Harrison and Kreps, but we prove …

2006-06-01abs ↗pdf ↗

This work improves the convergence theory of diffusion models for generating samples from complex distributions.

problem Improving theoretical understanding of diffusion models, particularly their convergence analysis.
method Developed an instance-dependent convergence rate that adapts to the smoothness of target distributions.
result Established an iteration complexity of min{d,d2/3L1/3,d1/3L}ε2/3\min\{d,d^{2/3}L^{1/3},d^{1/3}L\}\varepsilon^{-2/3} for generating high-quality samples.

Study bounds for Brownian motion on manifolds with sticky boundary conditions.

problem Proving geometric bounds for Brownian motion on manifolds with sticky boundary conditions.
method Interpolation involving energy interactions between boundary and interior of the manifold.
result Explicit geometric bounds on Steklov eigenvalues, boundary trace operators, and boundary trace logarithmic Sobolev constants.

Paper optimizes approximating high-dimensional diffusions by independent coordinates.

problem Optimizing approximations of high-dimensional diffusions by independent coordinates.
method Introduces independent projection as optimal for two criteria.
result Independent projection is optimal for two criteria related to entropy and convergence.

Study on policy gradient for stochastic bandits using diffusion approximation.

problem Improving policy gradient methods for stochastic bandits with optimal regret bounds.
method Continuous-time diffusion approximation of policy gradient with learning rate analysis.
result Proved optimal regret bound of O(klog(k)log(n)/η)O(k \log(k) \log(n) / η) for η=O(Δ2/log(n))η= O(Δ^2/\log(n)).

New bounds close the score matching gap for diffusion models.

problem The difference between sample quality and score matching loss in diffusion models.
method Theoretical analysis of score matching gap, developing tighter bounds for KL divergence, reverse KL divergence, and Wasserstein distance.
result The quality of score approximation impacts closing the score matching gap for low noise scales.

Diffusion models achieve high-quality samples from complex high-dimensional Gaussian mixtures without scaling with dimension.

problem Achieving accurate sampling from high-dimensional distributions using diffusion models.
method Investigates the effectiveness of diffusion models in sampling from Gaussian Mixture Models (GMMs) without scaling with dimension.
result DDPM requires at most O(1/ε)O(1/\varepsilon) iterations to attain an ε\varepsilon-accurate distribution in total variation distance, independent of dimension and number of components.

Sharp Lipschitz bounds for flow-matching and diffusion models with optimal sampling rates.

problem Establishing optimal Lipschitz regularity for flow-matching and diffusion models.
method Sharp Lipschitz regularity theory for flow-matching vector fields and diffusion-model scores.
result Achieves optimal sampling rate of d/N\sqrt{d}/N for Euler-type samplers in dimension dd.

Flow Matching improves statistical guarantees through kernel density estimation.

problem Improving statistical guarantees for generative models.
method Connecting Flow Matching to kernel density estimation and verifying optimal rates of convergence.
result Flow Matching achieves optimal rates up to logarithmic factors for large networks and on lower-dimensional manifolds.

Sharp 2-Wasserstein bounds for DDPMs derived from Föllmer process.

problem Sampling error bounds for DDPMs in 2-Wasserstein distance.
method Lipschitz-type conditions on score function, Föllmer process, and log-concave target distributions.
result Sharp upper bounds for DDPMs in 2-Wasserstein distance, optimal in dimension and steps.

FHDMs achieve optimal convergence in spherically supported data.

problem Statistical convergence properties of FHDMs for spherical data.
method FHDMs leverage random generation time and Doob's h-transform to optimize convergence rate.
result Achieve minimax optimal convergence rate in total variation for spherically supported Sobolev smooth data.

A stock market is called diverse if no stock can dominate the market in terms of relative capitalization. On one hand, this natural property leads to arbitrage in diffusion models under mild assumptions. On the other hand, it is also easy to construct diffusion models which are both diverse and free of arbitrage. Can o…

2013-01-17abs ↗pdf ↗

Affine jump-diffusions constitute a large class of continuous-time stochastic models that are particularly popular in finance and economics due to their analytical tractability. Methods for parameter estimation for such processes require ergodicity in order establish consistency and asymptotic normality of the associat…

2018-10-31abs ↗pdf ↗

For incomplete sub-Riemannian manifolds, and for an associated second-order hypoelliptic operator, which need not be symmetric, we identify two alternative conditions for the validity of Gaussian-type upper bounds on heat kernels and transition probabilities, with optimal constant in the exponent. Under similar conditi…

2018-10-15abs ↗pdf ↗

New theory improves diffusion model convergence for generating data.

problem Improving convergence of diffusion models for data generation.
method Developed a non-asymptotic convergence theory for probability flow ODEs.
result Proves d/εd/\varepsilon iterations suffice for approximating target distributions.

Improved image generation quality using closed-form discriminator guidance in diffusion models.

problem Enhancing the quality of images generated by diffusion models.
method Theoretical framework to analyze GAN discriminator's effect on Langevin sampling, proposing IPM-GAN optimization as smoothed score-matching.
result Closed-form kernel-based discriminator guidance improves metrics like CLIP-FID and KID.

New method aligns diffusion models for inference-time properties without retraining.

problem Aligning pre-trained diffusion models for desired inference-time properties.
method Variationally stable Doob's matching for provable guidance estimation.
result Consistent estimator of guidance with non-asymptotic convergence guarantees.

The paper develops a new probabilistic framework for denoising diffusion models using free entropy and stochastic analysis.

problem Developing a mathematical framework for denoising diffusion models in noncommutative settings.
method Formulating diffusion and reverse processes governed by operator-valued stochastic dynamics, using tools from free stochastic analysis.
result Establishing an information-geometric link between entropy production, transport, and deconvolution.

We study convexity and monotonicity properties for prices of bonds and bond options when the short rate is modeled by a diffusion process. We provide conditions under which convexity of the price in the short rate is guaranteed. Under these conditions the price is decreasing in the drift and increasing in the volatilit…

2007-02-15abs ↗pdf ↗

We present a simple dynamical model of stock index returns which is grounded on the ability of the Cyclically Adjusted Price Earning (CAPE) valuation ratio devised by Robert Shiller to predict long-horizon performances of the market. More precisely, we discuss a discrete time dynamics in which the return growth depends…

2012-04-23abs ↗pdf ↗

Paper establishes fast convergence theory for diffusion models under minimal assumptions.

problem Establish theoretical guarantees for diffusion models under minimal assumptions.
method Developed a convergence theory for denoising diffusion probabilistic models (DDPM) under minimal assumptions.
result Achieved convergence rate of O(d/T) for target distributions with finite first-order moment.

The paper improves the probability flow ODE sampler for faster sampling of natural images.

problem Improving the convergence rate of the probability flow ODE sampler.
method Adapting the probability flow ODE sampler to exploit intrinsic low-dimensional structures in natural image data.
result Achieves a dimension-free convergence rate of O(k/T)O(k/T) in total variation distance, improving upon existing results.

This work extends diffusion models to handle heavy-tailed targets, improving score estimation and sampling guarantees.

problem Score estimation and sampling guarantees for heavy-tailed targets in diffusion models.
method Kernel density estimation and minimax rates analysis for score estimation and sampling guarantees.
result Sharp minimax rates for score estimation and sampling guarantees for heavy-tailed targets, revealing qualitative differences between exponential and polynomial tails.

Graph diffusion processes approximate manifold heat semigroups using graph transition matrices.

problem Approximating manifold heat semigroups from graph data under low regularity conditions.
method Iterating graph transition matrix PP to approximate Qt=etΔQ_t = e^{tΔ}, bounding error in \infty-norm.
result Convergence rates O(N2/(d+6))O(N^{-2/(d+6)}) for manifold heat semigroup approximation, valid for in-sample and out-of-sample.

Study provides convergence guarantees for discrete diffusion models on finite and infinite state spaces.

problem Challenges in understanding discrete diffusion models on combinatorial state spaces.
method Established convergence bounds for three discrete diffusion models using Euler approximations.
result Optimal non-asymptotic convergence guarantees for discrete diffusion models without boundedness assumptions.

We investigate the mm-relative entropy, which stems from the Bregman divergence, on weighted Riemannian and Finsler manifolds. We prove that the displacement KK-convexity of the mm-relative entropy is equivalent to the combination of the nonnegativity of the weighted Ricci curvature and the KK-convexity of the weig…

2010-05-08abs ↗pdf ↗

The article examines entropy-information inequalities for continuous-time Markov chains under curvature-dimension conditions.

problem Proving Li-Yau inequalities and modified logarithmic Sobolev inequalities for reversible Markov chains.
method Introducing the CDΥ(κ,F)CD_Υ(κ,F) condition and deriving entropy-information inequalities.
result Derives functional inequalities relating entropy to Fisher information.

This work establishes near-minimax optimal guarantees for ODE-based samplers under mild assumptions.

problem Develop rigorous statistical guarantees for ODE-based samplers in generative modeling.
method Proposes a smooth regularized score estimator and refined convergence analysis.
result Achieves minimax rate in total variation distance for ODE-based samplers under mild assumptions.

New method calibrates stochastic reduced-order models from data efficiently.

problem Challenges in estimating drift and diffusion coefficients from data for high-dimensional systems.
method Uses a novel relationship between conditional score and transition density to constrain model coefficients directly from finite-lag statistics.
result Validated on various systems, the method reproduces statistical and dynamical properties of the original models.

Non-negative curvature affects Markov chains' mixing and expansion properties.

problem Understanding the behavior of Markov chains with non-negative curvature.
method Analyzing conductance, displacement, and cutoff phenomenon in sparse Markov chains.
result Non-negatively curved Markov chains exhibit specific, non-standard behavior in terms of mixing and expansion.