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In this work, we propose and study a framework of generalized proximal point algorithms associated with a maximally monotone operator. We indicate sufficient conditions on the regularization and relaxation parameters of generalized proximal…

Optimization and Control · Mathematics 2022-03-29 Hui Ouyang

Recently, two of the authors obtained estimates for the adjoint restriction operator to finite type curves with respect to general measures. Strikingly, it turns out that some of such estimates are sharp, especially when the measures are…

Classical Analysis and ODEs · Mathematics 2019-11-04 Seheon Ham , Hyerim Ko , Sanghyuk Lee

We consider a Hilbert space that is a product of a finite number of Hilbert spaces and operators that are represented by "componental operators" acting on the Hilbert spaces that form the product space. We attribute operatorial properties…

Functional Analysis · Mathematics 2021-11-30 Andrzej Cegielski , Yair Censor

This paper studies sparse covariance operator estimation for nonstationary processes with sharply varying marginal variance and small correlation lengthscale. We introduce a covariance operator estimator that adaptively thresholds the…

Statistics Theory · Mathematics 2025-06-23 Omar Al-Ghattas , Daniel Sanz-Alonso

Accretive and monotone operator theory are central branches of nonlinear functional analysis and constitute the abstract study of set-valued mappings between function spaces. This paper deals with the computational properties of certain…

Logic · Mathematics 2022-05-10 Nicholas Pischke

We study nearly equal and nearly convex sets, ranges of maximally monotone operators, and ranges and fixed points of convex combinations of firmly nonexpansive mappings. The main result states that the range of an average of firmly…

Functional Analysis · Mathematics 2011-05-03 Heinz H. Bauschke , Sarah M. Moffat , Xianfu Wang

We show that the set of projections in an operator system can be detected using only the abstract data of the operator system. Specifically, we show that if $p$ is a positive contraction in an operator system $V$ which satisfies certain…

Operator Algebras · Mathematics 2022-04-12 Roy Araiza , Travis Russell

We develop the method of averaging in Clifford (geometric) algebras suggested by the author in previous papers. We consider operators constructed using two different sets of anticommuting elements of real or complexified Clifford algebras.…

Mathematical Physics · Physics 2023-08-24 D. S. Shirokov

One-parameter generalizations of the logarithmic and exponential functions have been obtained as well as algebraic operators to retrieve extensivity. Analytical expressions for the successive applications of the sum or product operators on…

Projective splitting is a family of methods for solving inclusions involving sums of maximal monotone operators. First introduced by Eckstein and Svaiter in 2008, these methods have enjoyed significant innovation in recent years, becoming…

Optimization and Control · Mathematics 2020-02-19 Patrick R. Johnstone , Jonathan Eckstein

We describe the representation of arbitrary density operators in terms of expectation values of simple projection operators. Two representations are presented which yield non--recursive schemes for experimentally determining the density…

Quantum Physics · Physics 2009-10-28 Ole Steuernagel , John A. Vaccaro

We extend the theory of distributional kernel operators to a framework of generalized functions, in which they are replaced by integral kernel operators. Moreover, in contrast to the distributional case, we show that these generalized…

General Mathematics · Mathematics 2016-08-16 Séverine Bernard , Jean-François Colombeau , Antoine Delcroix

M-estimators for Generalized Linear Models are considered under minimal assumptions. Under these preliminaries, strong convergence of the estimators are discussed and an expansion of the estimating operators are given in the non-i.i.d. case…

Statistics Theory · Mathematics 2021-10-26 K. P. Chowdhury

We introduce a novel projection depth for data lying in a general Hilbert space, called the regularized projection depth, with a focus on functional data. By regularizing projection directions, the proposed depth does not suffer from the…

Methodology · Statistics 2025-12-24 Filip Bočinec , Stanislav Nagy , Hyemin Yeon

We introduce the class of $\alpha$-firmly nonexpansive and quasi $\alpha$-firmly nonexpansive operators on $r$-uniformly convex Banach spaces. This extends the existing notion from Hilbert spaces, where $\alpha$-firmly nonexpansive…

Functional Analysis · Mathematics 2025-03-11 Arian Bërdëllima , Gabriele Steidl

In this survey, we shall present characterizations of some distinguished classes of Hilbertian bounded linear operators (namely, normal operators, selfadjoint operators, and unitary operators) in terms of operator inequalities related to…

Functional Analysis · Mathematics 2020-07-03 Ameur Seddik

We examine the averaging operator $T$ corresponding to the manifold in $\mathbb{R}^{2d}$ of pairs of points $(u,v)$ satisfying $|u| = |v| = |u - v| = 1$, so that $\{0,u,v\}$ is the set of vertices of an equilateral triangle. We establish…

Classical Analysis and ODEs · Mathematics 2023-05-05 Eyvindur A. Palsson , Sean R. Sovine

Recent work by several authors has revealed the existence of many unexpected classes of normal weighted composition operators. On the other hand, it is known that every normal operator is a complex symmetric operator. We therefore undertake…

Functional Analysis · Mathematics 2012-05-22 Stephan Ramon Garcia , Christopher Hammond

Maximally monotone operators and firmly nonexpansive mappings play key roles in modern optimization and nonlinear analysis. Five years ago, it was shown that if finitely many firmly nonexpansive operators are all asymptotically regular…

Optimization and Control · Mathematics 2017-12-05 Heinz H. Bauschke , Walaa M. Moursi

This paper establishes optimal convergence rates for estimation of structured covariance operators of Gaussian processes. We study banded operators with kernels that decay rapidly off-the-diagonal and $L^q$-sparse operators with an…

Statistics Theory · Mathematics 2025-07-01 Omar Al-Ghattas , Jiaheng Chen , Daniel Sanz-Alonso , Nathan Waniorek