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We study two abstract scenarios, where an operator family has a certain minimality property. In both scenarios, it is shown that norm, spectrum and resolvent are the same for all family members. Both abstract settings are illustrated by…

Functional Analysis · Mathematics 2021-11-30 Marko Lindner

Min-max problems have broad applications in machine learning, including learning with non-decomposable loss and learning with robustness to data distribution. Convex-concave min-max problem is an active topic of research with efficient…

Optimization and Control · Mathematics 2021-05-12 Hassan Rafique , Mingrui Liu , Qihang Lin , Tianbao Yang

Sparse optimization refers to an optimization problem involving the zero-norm in objective or constraints. In this paper, nonconvex approximation approaches for sparse optimization have been studied with a unifying point of view in DC…

Numerical Analysis · Computer Science 2014-07-23 Hoai An Le Thi , Tao Pham Dinh , Hoai Minh Le , Xuan Thanh Vo

We introduce and analyze an algorithm for the minimization of convex functions that are the sum of differentiable terms and proximable terms composed with linear operators. The method builds upon the recently developed smoothed gap…

Optimization and Control · Mathematics 2017-06-20 Quang Van Nguyen , Olivier Fercoq , Volkan Cevher

Finding the minimum and the minimizers of convex functions has been of primary concern in convex analysis since its conception. It is well-known that if a convex function has a minimum, then that minimum is global. The minimizers, however,…

Optimization and Control · Mathematics 2014-10-07 C. Planiden , X. Wang

Convex-nonconvex (CNC) regularization is a novel paradigm that employs a nonconvex penalty function while maintaining the convexity of the entire objective function. It has been successfully applied to problems in signal processing,…

Optimization and Control · Mathematics 2025-02-21 Qiang Heng , Xiaoqian Liu , Eric C. Chi

Constrained optimization with multiple functional inequality constraints has significant applications in machine learning. This paper examines a crucial subset of such problems where both the objective and constraint functions are weakly…

Machine Learning · Computer Science 2026-02-09 Ming Yang , Gang Li , Quanqi Hu , Qihang Lin , Tianbao Yang

Projection operators arise naturally as one-particle density operators associated to Slater determinants in fields such as quantum mechanics and the study of determinantal processes. In the context of the semiclassical approximation of…

Mathematical Physics · Physics 2024-05-29 Laurent Lafleche

We show that the high-dimensional behavior of symmetrically penalized least squares with a possibly non-separable, symmetric, convex penalty in both (i) the Gaussian sequence model and (ii) the linear model with uncorrelated Gaussian…

Statistics Theory · Mathematics 2019-06-26 Michael Celentano

We consider operator-valued Herglotz functions and their applications to self-adjoint perturbations of self-adjoint operators and self-adjoint extensions of densely defined closed symmetric operators. Our applications include model…

Functional Analysis · Mathematics 2007-05-23 Fritz Gesztesy , Nigel J. Kalton , Konstantin A. Makarov , Eduard Tsekanovskii

Location estimation is a central problem in functional data analysis. In this paper, we investigate penalized spline estimators of location for discretely sampled functional data under a broad class of convex loss functions. Our framework…

Methodology · Statistics 2025-08-19 Ioannis Kalogridis

We study minimization of a structured objective function, being the sum of a smooth function and a composition of a weakly convex function with a linear operator. Applications include image reconstruction problems with regularizers that…

Optimization and Control · Mathematics 2021-06-01 Axel Böhm , Stephen J. Wright

We present a principled way of deriving a continuous relaxation of a given discontinuous shrinkage operator, which is based on two fundamental results, proximal inclusion and conversion. Using our results, the discontinuous operator is…

Optimization and Control · Mathematics 2025-06-17 Masahiro Yukawa

We propose a proximal variable smoothing algorithm for nonsmooth optimization problem with sum of three functions involving weakly convex composite function. The proposed algorithm is designed as a time-varying forward-backward splitting…

Optimization and Control · Mathematics 2025-04-29 Keita Kume , Isao Yamada

We provide comparison principles for convex functions through its proximal mappings. Consequently, we prove that the norm of the proximal operator determines a convex the function up to a constant. A new characterization of Lipschitzianity…

Optimization and Control · Mathematics 2020-07-30 Emilio Vilches

The notion of B-convexity for operator spaces, which a priori depends on a set of parameters indexed by $\Sigma$, is defined. Some of the classical characterizations of this geometric notion for Banach spaces are studied in this new…

Operator Algebras · Mathematics 2007-05-23 Javier Parcet

We propose a new class of exact continuous relaxations of l0-regularized criteria involving non-quadratic data terms such as the Kullback-Leibler divergence and the logistic regression, possibly combined with an l2 regularization. We first…

Optimization and Control · Mathematics 2025-08-26 M'hamed Essafri , Luca Calatroni , Emmanuel Soubies

We consider the problem of inferring the conditional independence graph (CIG) of high-dimensional Gaussian vectors from multi-attribute data. Most existing methods for graph estimation are based on single-attribute models where one…

Machine Learning · Statistics 2025-05-20 Jitendra K Tugnait

We study a family of (potentially non-convex) constrained optimization problems with convex composite structure. Through a novel analysis of non-smooth geometry, we show that proximal-type algorithms applied to exact penalty formulations of…

Optimization and Control · Mathematics 2019-03-04 Yu Bai , John Duchi , Song Mei

We consider minimization of functions that are compositions of convex or prox-regular functions (possibly extended-valued) with smooth vector functions. A wide variety of important optimization problems fall into this framework. We describe…

Optimization and Control · Mathematics 2015-04-24 A. S. Lewis , S. J. Wright