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The renormalization procedure of the non-linear SU(2) sigma model in D=4 proposed in hep-th/0504023 and hep-th/0506220 is here tested in a truly non-trivial case where the non-linearity of the functional equation is crucial. The simplest…

High Energy Physics - Theory · Physics 2009-11-11 Ruggero Ferrari , Andrea Quadri

In this paper, we investigate various properties (e.g., nonexistence, asymptotic behavior, uniqueness and integral representation formula) of positive solutions to nonlinear tri-harmonic equations in $\mathbb{R}^{n}$ ($n\geq2$) and…

Analysis of PDEs · Mathematics 2021-08-09 Wei Dai , Jingze Fu

We consider nonparametric regression with functional covariates, that is, they are elements of an infinite-dimensional Hilbert space. A locally polynomial estimator is constructed, where an orthonormal basis and various tuning parameters…

Statistics Theory · Mathematics 2025-04-09 Moritz Jirak , Alois Kneip , Alexander Meister , Mario Pahl

In this paper, we consider an elliptic operator obtained as the superposition of a classical second-order differential operator and a nonlocal operator of fractional type. Though the methods that we develop are quite general, for…

Analysis of PDEs · Mathematics 2020-06-11 Stefano Biagi , Serena Dipierro , Enrico Valdinoci , Eugenio Vecchi

This letter announces and summarizes results obtained in arXiv:1111.5051 and considers several natural extensions. The aforementioned paper proposes a procedure to reconstruct coefficients in a second-order, scalar, elliptic equation from…

Analysis of PDEs · Mathematics 2012-03-07 Guillaume Bal , Gunther Uhlmann

We investigate the nonperturbative renormalization of composite operators in lattice QCD restricting ourselves to operators that are bilinear in the quark fields. These include operators which are relevant to the calculation of moments of…

High Energy Physics - Lattice · Physics 2008-11-26 M. Gockeler , R. Horsley , H. Oelrich , H. Perlt , D. Petters , P. E. L. Rakow , A. Schafer , G. Schierholz , A. Schiller

We consider the third order operator with periodic coefficients on the real line. This operator is used in the integration of the non-linear evolution Boussinesq equation. For the minimal smoothness of the coefficients we prove that: 1) the…

Mathematical Physics · Physics 2011-12-21 A. Badanin , E. Korotyaev

We propose a globally convergent computational technique for the nonlinear inverse problem of reconstructing the zero-order coefficient in a parabolic equation using partial boundary data. This technique is called the "reduced dimensional…

Numerical Analysis · Mathematics 2023-09-27 Ray Abney , Thuy T. Le , Loc H. Nguyen , Cam Peters

Resolvent compositions were recently introduced as monotonicity-preserving operations that combine a set-valued monotone operator and a bounded linear operator. They generalize in particular the notion of a resolvent average. We analyze the…

Functional Analysis · Mathematics 2026-01-30 Diego J. Cornejo

Quasi-PDFs provide a path toward an ab initio calculation of parton distribution functions (PDFs) using lattice QCD. One of the problems faced in calculations of quasi-PDFs is the renormalization of a nonlocal operator. By introducing an…

High Energy Physics - Lattice · Physics 2018-07-18 Jeremy Green , Karl Jansen , Fernanda Steffens

The trichotomy between regular, semiregular, and strongly irregular boundary points for $p$-harmonic functions is obtained for unbounded open sets in complete metric spaces with a doubling measure supporting a $p$-Poincar\'e inequality,…

Analysis of PDEs · Mathematics 2022-07-15 Anders Björn , Daniel Hansevi

We obtain new concavity results, up to a suitable transformation, for a class of quasi-linear equations in a convex domain involving the $p$-Laplace operator and a general nonlinearity satisfying concavity type assumptions. This provides an…

Analysis of PDEs · Mathematics 2022-02-01 William Borrelli , Sunra Mosconi , Marco Squassina

In this work, we study the renormalization of nonlocal quark bilinear operators containing an asymmetric staple-shaped Wilson line at the one-loop level in both lattice and continuum perturbation theory. These operators enter the…

High Energy Physics - Lattice · Physics 2024-06-10 Gregoris Spanoudes , Martha Constantinou , Haralambos Panagopoulos

We consider the problem of asymptotic reconstruction of the state and parameter values in systems of ordinary differential equations. A solution to this problem is proposed for a class of systems of which the unknowns are allowed to be…

Optimization and Control · Mathematics 2015-03-13 Ivan Y. Tyukin , Erik Steur , Henk Nijmeijer , Cees van Leeuwen

In this paper, we investigate the reconstruction of a bivariate function from weighted edge integrals on a triangular mesh, a problem of central importance in tomography, computer vision, and numerical approximation. Our approach is based…

Numerical Analysis · Mathematics 2025-11-12 Gradimir V. Milovanovic , Federico Nudo

This paper is concerned with the question of reconstructing a vector in a finite-dimensional real Hilbert space when only the magnitudes of the coefficients of the vector under a redundant linear map are known. We analyze various Lipschitz…

Functional Analysis · Mathematics 2013-08-23 Radu Balan , Yang Wang

The purpose of the paper is to introduce and study a new class of operators on semi-Hilbertian spaces i.e.; spaces generated by positive semidefinite sesquilinear forms. Let H be a Hilbert space and let A be a positive bounded operator on H…

General Mathematics · Mathematics 2019-12-09 Samir Al Mohammady , Sid Ahmed Ould Beinane , Sid Ahmed O. Ahmed Mahmoud

We consider in this paper two different types of the weighted geometric means of positive definite operators. We show the component-wise bijection of these geometric means and give a geometric property of the spectral geometric mean as a…

Functional Analysis · Mathematics 2020-09-23 Sejong Kim

We extend projectively equivariant quantization and symbol calculus to symbols of pseudo-differential operators. An explicit expression in terms of hypergeometric functions with noncommutative arguments is given. Some examples are worked…

Quantum Algebra · Mathematics 2007-05-23 C. Duval , V. Ovsienko

A reexamination is made of one-loop oblique electroweak corrections. General definitions are given of the oblique parameters without reference to any $q^2$-expansion scheme. The old oblique parameters S,T and U are defined as differences of…

High Energy Physics - Phenomenology · Physics 2014-11-17 Anirban Kundu , Probir Roy