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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.

168,695 papers · 148 categories

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55109164218 · Jun 202019922001200920172026
48 results for logarithmic convexity

The present note is a result of an on-going investigation into the logarithmic Brunn-Minkowski inequality. We obtain lower estimates on the volume product for convex bodies in Rn\mathbb{R}^n not necessarily symmetric with respect to the origin from a modified logarithmic Brunn-Minkowski inequality.

2014-04-30abs ↗pdf ↗

Adaptive gradient methods have become recently very popular, in particular as they have been shown to be useful in the training of deep neural networks. In this paper we have analyzed RMSProp, originally proposed for the training of deep neural networks, in the context of online convex optimization and show T\sqrt{T}-…

2017-06-17abs ↗pdf ↗

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 ↗

Paper generalizes VB-FTRL for online learning of quantum states with logarithmic loss.

problem Online learning of quantum states with logarithmic loss.
method Generalizes VB-FTRL algorithm for LL-OLQS with polynomial-time implementation.
result Achieves a regret rate of O(d2log(d+T))O (d^2 \log (d + T)) for LL-OLQS.

New uncertainty principle for Schrödinger equations on hyperbolic manifolds.

problem Uncertainty principle for Schrödinger equations on hyperbolic manifolds.
method General strategy of Escauriaza-Kenig-Ponce-Vega, new Carleman estimates, logarithmic convexity, new mollifier and weight function.
result Similar rigidity phenomenon as in Euclidean space persists in hyperbolic geometry.

Develops a parameter-free SGD algorithm with optimal convergence rate.

problem Optimizing parameters in stochastic convex optimization.
method A novel parameter-free algorithm for SGD with high-probability guarantees and adaptive properties.
result Achieves optimal convergence rate with only a double-logarithmic factor increase compared to known-parameter settings.

New algorithm exploits curvature of feasible sets for fast online convex optimization.

problem Online convex optimization with fast rates.
method Adapting FTL algorithm to curvature of feasible sets.
result Achieves logarithmic regret bound of O(ρlogT)O(ρ\log T) in stochastic environments.

Paper connects Fenchel-Willmore and Sobolev inequalities for submanifolds in curved spaces.

problem Developing inequalities for submanifolds in curved spaces.
method Connecting Fenchel-Willmore and logarithmic Sobolev inequalities for mean-convex submanifolds.
result Established extensions of Fenchel-Willmore inequality and derived new Sobolev-type inequalities.

LMC algorithm converges to target in Chi-squared and Renyi divergence.

problem Sampling from target distribution using LMC with strong dissipativity and smoothness conditions.
method LMC algorithm with strong dissipativity and first-order smoothness, initialized with Gaussian.
result LMC reaches ε-neighborhood of target in Chi-squared and Renyi divergence in O(λ²dε⁻¹) steps.

Paper solves minimax optimization gap with near-optimal algorithms.

problem Designing efficient algorithms for smooth and strongly-convex-strongly-concave minimax problems.
method Accelerated proximal point method and accelerated solver for minimax proximal steps.
result First algorithm with gradient complexity matching the lower bound up to logarithmic factors.

The conformal Codazzi structure is an intrinsic geometric structure on strictly convex hypersufaces in a locally flat projective manifold. We construct the GJMS operators and the Q-curvature for conformal Codazzi structures by using the ambient metric. We relate the total Q-curvature to the logarithmic coefficient in t…

2016-02-08abs ↗pdf ↗

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 ↗

We introduce a class of generalized relative entropies (inspired by the Bregman divergence in information theory) on the Wasserstein space over a weighted Riemannian or Finsler manifold. We prove that the convexity of all the entropies in this class is equivalent to the combination of the nonnegative weighted Ricci cur…

2011-12-23abs ↗pdf ↗

We prove the Fundamental Gap Conjecture, which states that the difference between the first two Dirichlet eigenvalues (the spectral gap) of a Schrödinger operator with convex potential and Dirichlet boundary data on a convex domain is bounded below by the spectral gap on an interval of the same diameter with zero poten…

2010-06-09abs ↗pdf ↗

New Finsler metrics describe trace function growth rates in convex projective surfaces.

problem Understanding growth rates of trace functions in convex projective surfaces.
method Introduced new Finsler metrics and showed their convergence to describe trace function growth.
result Logarithms of trace functions are approximated by lengths in a Finsler metric defined by cubic differential.

The Adam algorithm has become extremely popular for large-scale machine learning. Under convexity condition, it has been proved to enjoy a data-dependant O(T)O(\sqrt{T}) regret bound where TT is the time horizon. However, whether strong convexity can be utilized to further improve the performance remains an open problem…

2019-05-08abs ↗pdf ↗

Two-stage nonconvex algorithm and convex relaxation both achieve optimal accuracy in noisy blind deconvolution.

problem Solving bilinear systems of equations with random noise under different designs.
method Two-stage nonconvex algorithm and convex relaxation.
result Both methods achieve minimax-optimal accuracy in the presence of random noise.

Unified analysis of online optimization with self-concordant barriers, improving regret bounds.

problem Online convex optimization with specific loss functions.
method Online mirror descent with self-concordant barriers and logarithmic loss.
result Improved regret bounds for online portfolio selection and quantum state learning.

The dueling bandit is a learning framework wherein the feedback information in the learning process is restricted to a noisy comparison between a pair of actions. In this research, we address a dueling bandit problem based on a cost function over a continuous space. We propose a stochastic mirror descent algorithm and …

2017-11-21abs ↗pdf ↗

New algorithm optimizes convex functions with noisy evaluations in one dimension.

problem Optimizing convex functions with noisy zero-order evaluations in one dimension.
method Proposed a computationally efficient algorithm achieving O(1/T)O(1/\sqrt{T}) convergence rate.
result Achieved the optimal O(1/T)O(1/\sqrt{T}) convergence rate, closing the gap in one dimension.

Let MM be a pinched negatively curved Riemannian manifold, whose unit tangent bundle is endowed with a Gibbs measure mFm_F associated to a potential FF. We compute the Hausdorff dimension of the conditional measures of mFm_F. We study the mFm_F-almost sure asymptotic penetration behaviour of locally geodesic lines of…

2014-05-09abs ↗pdf ↗

Least Squares Estimators are suboptimal for 5D convex functions.

problem Suboptimality of Least Squares Estimators in estimating multidimensional convex functions.
method Analysis of natural subclasses of convex functions in random and fixed design settings.
result Risk of LSE is n2/dn^{-2/d} while minimax risk is n4/(d+4)n^{-4/(d+4)} for d5d \geq 5.

The online meta-learning framework is designed for the continual lifelong learning setting. It bridges two fields: meta-learning which tries to extract prior knowledge from past tasks for fast learning of future tasks, and online-learning which deals with the sequential setting where problems are revealed one by one. I…

2019-10-22abs ↗pdf ↗

Optimizes privacy-preserving optimization for heavy-tailed data.

problem Privacy-preserving optimization with heavy-tailed gradients.
method Pure ε-differential privacy framework for Lipschitz extensions.
result Minimax optimal excess-risk rate for pure ε-DP heavy-tailed SCO.

Optimizes private learning with differential privacy for LASSO problems.

problem Private optimization of convex functions over 1\ell_1-bounded domains.
method Combines iterative localization with private regularized mirror descent and variance-reduced Frank-Wolfe algorithm.
result Achieves optimal excess population loss rates in 1\ell_1 geometry.

The reach of a submanifold is a crucial regularity parameter for manifold learning and geometric inference from point clouds. This paper relates the reach of a submanifold to its convexity defect function. Using the stability properties of convexity defect functions, along with some new bounds and the recent submanifol…

2020-01-22abs ↗pdf ↗

In this paper, we study the optimal convergence rate for distributed convex optimization problems in networks. We model the communication restrictions imposed by the network as a set of affine constraints and provide optimal complexity bounds for four different setups, namely: the function $F(\xb) \triangleq \sum_{i=1}…

2017-12-01abs ↗pdf ↗

Paper presents a new framework for covariance matrix estimation with geometric insights.

problem Challenges in covariance matrix estimation, especially in finding suitable models and efficient estimation methods.
method General framework for linear restrictions on different transformations of the covariance matrix, including matrix logarithm and its inverse.
result Yields an MM-estimator with MM-estimation allowing for straightforward asymptotic and finite sample analysis.

Paper shows linear convergence of ISTA and FISTA for ill-conditioned images.

problem Solving linear inverse problems with sparse representation in signal and image processing.
method Revisits iterative shrinkage-thresholding algorithms (ISTA) and improves their convergence properties.
result Linear convergence of ISTA and FISTA for strongly convex smooth parts, even in ill-conditioned cases.

Study on lengths and curvatures of harmonic functions on smooth and singular surfaces.

problem Investigate logarithmic convexity and isoperimetric inequalities of harmonic functions on surfaces.
method Analyzes geodesic curvature, uses Laplace-type equations, and studies growth estimates.
result Generalizes results on logarithmic convexity and isoperimetric inequalities for harmonic functions.

Paper proposes efficient cost functions for automated market makers in DeFi.

problem Inefficient and computationally complex cost functions in DeFi.
method Proposes and analyzes constant circle/ellipse based cost functions.
result Proposed cost functions are computationally efficient and robust against attacks.

We introduce a temperature into the exponential function and replace the softmax output layer of neural nets by a high temperature generalization. Similarly, the logarithm in the log loss we use for training is replaced by a low temperature logarithm. By tuning the two temperatures we create loss functions that are non…

2019-06-08abs ↗pdf ↗

In this paper, we provide near-optimal accelerated first-order methods for minimizing a broad class of smooth nonconvex functions that are strictly unimodal on all lines through a minimizer. This function class, which we call the class of smooth quasar-convex functions, is parameterized by a constant γ(0,1]γ\in (0,1], wher…

2019-06-27abs ↗pdf ↗

The paper studies the convex hull of random points in a triangle, focusing on the asymptotic behavior and phase transitions.

problem Analyzing the convex hull of random points in a triangle with a phase transition.
method Conditional analysis of the convex hull's boundary size and shape, proving phase transitions and convergence to specific curves.
result The convex hull's boundary converges to a hyperbola or parabola under specific conditions, solving an optimization problem.

Optimal switching regret for all segmentations in online convex optimisation.

problem Non-stationary online convex optimisation problems.
method Developed an efficient algorithm to achieve optimal switching regret on every possible segmentation.
result Achieved asymptotically optimal switching regret on every possible segmentation simultaneously.

New bounds for online portfolio selection without smoothness assumptions.

problem Online portfolio selection with non-Lipschitz, non-smooth losses.
method Data-dependent bounds using novel smoothness characterizations and FTRL with self-concordant regularizers.
result Achieves logarithmic regrets when data is 'easy' and sublinear worst-case regrets.