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The paper studies strictly positive definite kernels on compact Riemannian manifolds. We state new conditions to ensure strict positive definiteness for general kernels and kernels with certain convolutional structure. We also state…

Numerical Analysis · Mathematics 2023-01-20 Jean Carlo Guella , Janin Jäger

Kernels are efficient in representing nonlocal dependence and they are widely used to design operators between function spaces. Thus, learning kernels in operators from data is an inverse problem of general interest. Due to the nonlocal…

Machine Learning · Statistics 2024-10-21 Neil K. Chada , Quanjun Lang , Fei Lu , Xiong Wang

The theory of positive kernels and associated reproducing kernel Hilbert spaces, especially in the setting of holomorphic functions, has been an important tool for the last several decades in a number of areas of complex analysis and…

Operator Algebras · Mathematics 2016-02-03 Joseph A. Ball , Gregory Marx , Victor Vinnikov

Practically applicable criteria for the nonclassicality of quantum states are formulated in terms of different types of moments. For this purpose the moments of the creation and annihilation operators, of two quadratures, and of a…

Quantum Physics · Physics 2009-11-11 E. V. Shchukin , W. Vogel

The effect of quantum fluctuations on a nearly flat, nonrelativistic two-dimensional membrane with extrinsic curvature stiffness and tension is investigated. The renormalization group analysis is carried out in first-order perturbative…

Condensed Matter · Physics 2009-10-31 M. E. S. Borelli , H. Kleinert , Adriaan M. J. Schakel

The kernel Maximum Mean Discrepancy~(MMD) is a popular multivariate distance metric between distributions that has found utility in two-sample testing. The usual kernel-MMD test statistic is a degenerate U-statistic under the null, and thus…

Methodology · Statistics 2025-09-16 Shubhanshu Shekhar , Ilmun Kim , Aaditya Ramdas

When a quantum phase transition is crossed within a finite time, critical slowing down disrupts adiabatic dynamics, resulting in the formation of topological defects. The average density of these defects scales with the quench rate,…

Quantum Physics · Physics 2025-06-12 Oriel Kiss , Daniil Teplitskiy , Michele Grossi , Antonio Mandarino

We show that a positive operator between $L^p$-spaces is given by integration against a kernel function if and only if the image of each positive function has a lower semi-continuous representative with respect to a suitable topology. This…

Functional Analysis · Mathematics 2024-06-11 Moritz Gerlach , Jochen Glück

The decoherence rate of a quantum dot coupled to a fluctuating environment described by a normal-metal superconductor junction is considered. The density-density correlator at low frequencies constitutes the kernel which enters the…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 Rodolphe Guyon , Thierry Martin , Gordey B. Lesovik

Given a $2$-step stratified group which does not satisfy a slight strengthening of the Moore-Wolf condition, a sub-Laplacian $\mathcal{L}$ and a family $\mathcal{T}$ of elements of the derived algebra, we study the convolution kernels…

Functional Analysis · Mathematics 2020-03-31 Mattia Calzi

Cultured stem cells have become a standard platform not only for regenerative medicine and developmental biology but also for biophysical studies. Yet, the characterization of cultured stem cells at the level of morphology and macroscopic…

Soft Condensed Matter · Physics 2022-06-23 Kyogo Kawaguchi , Ryoichiro Kageyama , Masaki Sano

High-dimensional data in the form of tensors are challenging for kernel classification methods. To both reduce the computational complexity and extract informative features, kernels based on low-rank tensor decompositions have been…

Machine Learning · Statistics 2023-02-17 Kirandeep Kour , Sergey Dolgov , Peter Benner , Martin Stoll , Max Pfeffer

The consistency of a learning method is usually established under the assumption that the observations are a realization of an independent and identically distributed (i.i.d.) or mixing process. Yet, kernel methods such as support vector…

Machine Learning · Computer Science 2024-06-11 Pierre-François Massiani , Sebastian Trimpe , Friedrich Solowjow

A symmetry-preserving treatment of mesons, within a Dyson-Schwinger and Bethe-Salpeter equations approach, demands an interconnection between the kernels of the quark gap equation and meson Bethe-Salpeter equation. Appealing to those…

Nuclear Theory · Physics 2021-10-04 Zanbin Xing , Khépani Raya , Lei Chang

Higher-dimensional entanglement is a valuable resource for several quantum information processing tasks, and is often characterized by the Schmidt number and specific classes of entangled states beyond qubit-qubit and qubit-qutrit systems.…

Quantum Physics · Physics 2025-07-28 Bivas Mallick , Ananda G. Maity , Nirman Ganguly , A. S. Majumdar

Asymptotic forms of the Hilbert-Scmidt and Hilbert norms of positive definite Toeplitz matrices $Q_{N}=(b(j-k))_{j,k=0}^{N-1}$ as $N\to \infty $ are determined. Here $b(j)$ are consequent trigonometric moments of a generating non-negative…

Spectral Theory · Mathematics 2007-05-23 Vadim M Adamyan , Jose L Iserte , Igor M Tkachenko

Let $X=(X_1,X_2,\ldots)$ be a sequence of random variables with values in a standard space $(S,\mathcal{B})$. Suppose \begin{gather*} X_1\sim\nu\quad\text{and}\quad P\bigl(X_{n+1}\in\cdot\mid…

Probability · Mathematics 2022-04-05 Patrizia Berti , Emanuela Dreassi , Fabrizio Leisen , Luca Pratelli , Pietro Rigo

We show that if a permutation statistic can be written as a linear combination of bivincular patterns, then its moments can be expressed as a linear combination of factorials with constant coefficients. This generalizes a result of…

Combinatorics · Mathematics 2021-09-21 Stoyan Dimitrov , Niraj Khare

The principal theorem of Sz.-Nagy on dilation of a positive definite Hilbert space operator valued function has played a central role in the development of the non-self-adjoint operator theory. In this paper we introduce the positive…

Functional Analysis · Mathematics 2015-04-30 Dumitru Gaşpar , Păstorel Gaşpar , Nicolae Lupa

The notion of a two-point susceptibility kernel used to describe linear electromagnetic responses of dispersive continuous media in non-relativistic phenomena is generalized to accommodate the constraints required of a causal formulation in…

Plasma Physics · Physics 2015-05-27 Jonathan Gratus , Robin W Tucker