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In this paper, we describe the general framework to describe the diffusion operators associated to a positive matrix. We define the equations associated to diffusion operators and present some general properties of their state vectors. We…

Numerical Analysis · Mathematics 2012-06-19 Dohy Hong , Gérard Burnside

The goal of this paper is to study certain p-adic differential operators on automorphic forms on U(n,n). These operators are a generalization to the higher-dimensional, vector-valued situation of the p-adic differential operators…

Number Theory · Mathematics 2013-02-01 Ellen E. Eischen

The statistical analysis of covariance matrices occurs in many important applications, e.g. in diffusion tensor imaging and longitudinal data analysis. We consider the situation where it is of interest to estimate an average covariance…

Methodology · Statistics 2010-10-20 Ian L. Dryden , Alexey Kolydenko , Diwei Zhou , Bai Li

A generalized eigenvector of a hypermatrix, called the universal (U-) eigenvector, is proposed, which extended the notion of diagonal (D-) eigenvectors in the literature. Using the semi-tensor product, the homogeneous U-eigenequation can be…

Numerical Analysis · Mathematics 2025-07-08 Daizhan Cheng , Zhengping Ji

The theory of degenerate parabolic equations of the forms \[ u_t=(\Phi(u_x))_{x} \quad {\rm and} \quad v_{t}=(\Phi(v))_{xx} \] is used to analyze the process of contour enhancement in image processing, based on the evolution model of…

Dynamical Systems · Mathematics 2007-05-23 G. I. Barenblatt , J. L. Vazquez

We integrate neural operators with diffusion models to address the spectral limitations of neural operators in surrogate modeling of turbulent flows. While neural operators offer computational efficiency, they exhibit deficiencies in…

Machine Learning · Computer Science 2025-02-14 Vivek Oommen , Aniruddha Bora , Zhen Zhang , George Em Karniadakis

The aim of this paper is to present some results about generation, sectoriality and gradient estimates both for the semigroup and for the resolvent of suitable realizations of the operators [\Ab u(x)=\gamma xu"(x) + b u'(x),] with constants…

Functional Analysis · Mathematics 2013-02-14 Angela A. Albanese , Elisabetta M. Mangino

This paper concerns the long-time asymptotics of diffusions with degenerate coefficients at the domain's boundary. Degenerate diffusion operators with mixed linear and quadratic degeneracies find applications in the analysis of asymmetric…

Analysis of PDEs · Mathematics 2022-11-04 Guillaume Bal , Binglu Chen , Zhongjian Wang

We provide a general method to analyze the asymptotic properties of a variety of estimators of continuous time diffusion processes when the data are not only discretely sampled in time but the time separating successive observations may…

Statistics Theory · Mathematics 2007-06-13 Yacine Ait-Sahalia , Per A. Mykland

Age-structured models with nonlocal diffusion arise naturally in describing the population dynamics of biological species and the transmission dynamics of infectious diseases in which individuals disperse nonlocally and interact each other…

Analysis of PDEs · Mathematics 2022-05-20 Arnaud Ducrot , Hao Kang , Shigui Ruan

We prove the decomposition of arbitrary diagonal operators into tensor and matrix products of smaller matrices, focusing on the analytic structure of the resulting formulas and their inherent symmetries. Diagrammatic representations are…

Quantum Physics · Physics 2025-10-15 M. M. Fedin , A. A. Morozov

In this paper we study a nonlocal diffusion problem on a manifold. These kind of equations can model diffusions when there are long range effects and have been widely studied in Euclidean space. We first prove existence and uniqueness of…

Analysis of PDEs · Mathematics 2015-11-02 Catherine Bandle , Maria del Mar Gonzalez , Marco A. Fontelos , Noemi Wolanski

The nonparametric estimation of integrated diffusion processes has been extensively studied, with most existing research focusing on pointwise convergence. This paper is the first to establish uniform convergence rates for the…

Statistics Theory · Mathematics 2025-03-20 Shaolin Ji , Linlin Zhu

A central problem in data analysis is the low dimensional representation of high dimensional data, and the concise description of its underlying geometry and density. In the analysis of large scale simulations of complex dynamical systems,…

Numerical Analysis · Mathematics 2007-05-23 Boaz Nadler , Stephane Lafon , Ronald R. Coifman , Ioannis G. Kevrekidis

We consider time-changed diffusions driven by generators with discontinuous coefficients. The PDE's connections are investigated and in particular some results on the asymptotic analysis according to the behaviour of the coefficients are…

Probability · Mathematics 2016-10-03 Raffaela Capitanelli , Mirko D'Ovidio

We present an efficient method to compute the eigenvalues and eigenmodes of the diffusion operator $\nabla(D\nabla)$ on one-dimensional heterogeneous structures with multiple semi-permeable barriers. This method allows us to calculate the…

Computational Physics · Physics 2019-02-25 Nicolas Moutal , Denis Grebenkov

The properties of diffusion processes are drastically affected by heterogeneities of the medium that can induce non-Gaussian behavior of the propagator in contrast with the idealized realm of Brownian motion. In this paper we analyze the…

Statistical Mechanics · Physics 2019-11-05 Yann Lanoiselée , Denis S. Grebenkov

We consider the problem of constructing diffusion operators high dimensional data $X$ to address counterfactual functions $F$, such as individualized treatment effectiveness. We propose and construct a new diffusion metric $K_F$ that…

Machine Learning · Statistics 2017-04-13 Alexander Cloninger

We investigate the effect of small diffusion on the principal eigenvalues of linear time-periodic parabolic operators with zero Neumann boundary conditions in one dimensional space. The asymptotic behaviors of the principal eigenvalues, as…

Analysis of PDEs · Mathematics 2021-01-13 Shuang Liu , Yuan Lou , Rui Peng , Maolin Zhou

In this article, we propose a reduced basis method for parametrized non-symmetric eigenvalue problems arising in the loading pattern optimization of a nuclear core in neutronics. To this end, we derive a posteriori error estimates for the…

Numerical Analysis · Mathematics 2023-07-13 Yonah Conjungo Taumhas , Geneviève Dusson , Virginie Ehrlacher , Tony Lelièvre , François Madiot