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In this paper, we are interested in investigating a weighted variant of Hermite-Hadamard type inequalities involving convex functionals. The approach undertaken makes it possible to refine and reverse certain inequalities already known in…

Functional Analysis · Mathematics 2024-05-21 Mustapha Raissouli , Mohamed Chergui , Lahcen Tarik

Uniform random rotations are a useful primitive in applications such as fast Johnson-Lindenstrauss embeddings, kernel approximation, communication-efficient learning, and recent AI compression pipelines, but they are computationally…

Machine Learning · Computer Science 2026-04-28 Tomer Zilca , Gal Mendelson

We study the finite-time convergence of projected linear two-time-scale stochastic approximation with constant step sizes and Polyak--Ruppert averaging. We establish an explicit mean-square error bound, decomposing it into two interpretable…

Systems and Control · Electrical Eng. & Systems 2026-04-02 Yitao Bai , Thinh T. Doan , Justin Romberg

We address the problem of testing hypotheses about a specific value of the Fr\'echet mean in metric spaces, extending classical mean testing from Euclidean spaces to more general settings. We extend an Euclidean testing procedure…

Methodology · Statistics 2025-01-28 Matthieu Bulté , Helle Sørensen

This paper studies the infinite-dimensional Bayesian inference method with Hadamard fractional total variation-Gaussian (HFTG) prior for solving inverse problems. First, Hadamard fractional Sobolev space is established and proved to be a…

Statistics Theory · Mathematics 2021-11-01 Li-Li Wang , Ming-Hui Ding , Guang-Hui Zheng

We provide conditions that guarantee local rates of convergence in distribution of iterated random functions that are not nonexpansive mappings in locally compact Hadamard spaces. Our results are applied to stochastic instances of common…

Probability · Mathematics 2023-11-01 Neal Hermer , D. Russell Luke , Anja Sturm

The work develops further the theory of the following inversion problem, which plays the central role in the rapidly developing area of thermoacoustic tomography and has intimate connections with PDEs and integral geometry: {\it Reconstruct…

Classical Analysis and ODEs · Mathematics 2011-08-04 Yuri A. Antipov , Ricardo Estrada , Boris Rubin

Inspired by a recent article on Fr\'echet spaces of ordinary Dirichlet series $\sum a_n n^{-s}$ due to J.~Bonet, we study topological and geometrical properties of certain scales of Fr\'echet spaces of general Dirichlet spaces $\sum a_n…

Functional Analysis · Mathematics 2020-12-16 Andreas Defant , Tomas Fernandez-Vidal , Ingo Schoolmann , Pablo Sevilla-Peris

This paper develops the first decentralized online Riemannian optimization algorithm on Hadamard manifolds. Our algorithm, the decentralized projected Riemannian gradient descent, iteratively performs local updates using projected…

Optimization and Control · Mathematics 2024-10-08 Hengchao Chen , Qiang Sun

Frechet's classical isometric embedding argument has evolved to become a major tool in the study of metric spaces. An important example of a Frechet embedding is Bourgain's embedding. The authors have recently shown that for every e>0 any…

Metric Geometry · Mathematics 2009-03-23 Yair Batal , Nathan Linial , Manor Mendel , Assaf Naor

It is well known, that Fr\'echet means on non-Euclidean spaces may exhibit nonstandard asymptotic rates depending on curvature. Even for distributions featuring standard asymptotic rates, there are non-Euclidean effects, altering finite…

Methodology · Statistics 2023-05-18 Susanne Ulmer , Do Tran Van , Stephan F. Huckemann

In this paper, we prove a mean ergodic theorem for nonexpansive mappings in Hadamard (nonpositive curvature metric) spaces, which extends the Baillon nonlinear ergodic theorem. The main result shows that the sequence given by the Karcher…

Functional Analysis · Mathematics 2021-05-07 Hadi Khatibzadeh , Hadi Pouladi

The classical and extensively-studied Fr\'echet distance between two curves is defined as an inf max, where the infimum is over all traversals of the curves, and the maximum is over all concurrent positions of the two agents. In this…

Computational Geometry · Computer Science 2022-09-22 Omrit Filtser , Mayank Goswami , Joseph S. B. Mitchell , Valentin Polishchuk

We consider a linear ill-posed equation in the Hilbert space setting. Multiple independent unbiased measurements of the right hand side are available. A natural approach is to take the average of the measurements as an approximation of the…

Numerical Analysis · Mathematics 2021-09-01 Tim Jahn

Drawing statistical inferences from large datasets in a model-robust way is an important problem in statistics and data science. In this paper, we propose methods that are robust to large and unequal noise in different observational units…

Statistics Theory · Mathematics 2024-01-10 Edgar Dobriban , Weijie J. Su , Yachong Yang , Zhixiang Zhang

We devise a new embedding technique, which we call measured descent, based on decomposing a metric space locally, at varying speeds, according to the density of some probability measure. This provides a refined and unified framework for the…

Data Structures and Algorithms · Computer Science 2007-05-23 Robert Krauthgamer , James R. Lee , Manor Mendel , Assaf Naor

A Fr\'echet mean of a random variable $Y$ with values in a metric space $(\mathcal Q, d)$ is an element of the metric space that minimizes $q \mapsto \mathbb E[d(Y,q)^2]$. This minimizer may be non-unique. We study strong laws of large…

Probability · Mathematics 2025-08-04 Christof Schötz

We consider empirical measures of $\R^{d}$-valued stochastic process in finite discrete-time. We show that the adapted empirical measure introduced in the recent work \cite{backhoff2022estimating} by Backhoff et al. in compact spaces can be…

Probability · Mathematics 2023-10-25 Beatrice Acciaio , Songyan Hou

Across many scientific disciplines, multiple observations are collected from the same experimental units, and in modern datasets these observations often arise as non-Euclidean random objects. In such settings, the incorporation of random…

Machine Learning · Statistics 2026-05-05 Marcos Matabuena , Mateo Cámara

We provide efficient and intuitive tools for deriving bounds on achievable precision in quantum enhanced metrology based on the geometry of quantum channels and semi-definite programming. We show that when decoherence is taken into account,…

Quantum Physics · Physics 2012-09-19 Rafal Demkowicz-Dobrzanski , Jan Kolodynski , Madalin Guta