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In this note we study the eigenvalue problem for a quadratic form associated with Strichartz estimates for the Schr\"{o}dinger equation, proving in particular a sharp Strichartz inequality for the case of odd initial data. We also describe…

Classical Analysis and ODEs · Mathematics 2022-02-08 Felipe Gonçalves , Don Zagier

We consider the nonlinear eigenvalue problem, with Dirichlet boundary condition, for a class of very degenerate elliptic operators, with the aim to show that, at least for square type domains having fixed volume, the symmetry of the domain…

Analysis of PDEs · Mathematics 2018-03-21 Isabeau Birindelli , Giulio Galise , Hitoshi Ishii

Laplacian eigenmap algorithm is a typical nonlinear model for dimensionality reduction in classical machine learning. We propose an efficient quantum Laplacian eigenmap algorithm to exponentially speed up the original counterparts. In our…

Quantum Physics · Physics 2016-11-04 Yiming Huang , Xiaoyu Li

We consider the two-dimensional eigenvalue problem for the Laplacian with the Neumann boundary condition involving the critical Hardy potential. We prove the existence of the second eigenfunction and study its asymptotic behavior around the…

Analysis of PDEs · Mathematics 2022-10-20 Megumi Sano , Futoshi Takahashi

The eigenvalue problem of the spherically symmetric oscillator Hamiltonian is revisited in the context of canonical raising and lowering operators. The Hamiltonian is then factorized in terms of two not mutually adjoint factorizing…

Quantum Physics · Physics 2009-02-26 Ivan Cabrera-Munguia , Oscar Rosas-Ortiz

Finding the eigenvalues of a Sturm-Liouville problem can be a computationally challenging task, especially when a large set of eigenvalues is computed, or just when particularly large eigenvalues are sought. This is a consequence of the…

Numerical Analysis · Mathematics 2009-11-13 Veerle Ledoux , Marnix Van Daele , Guido Vanden Berghe

We prove existence, uniqueness and regularity results for mixed boundary value problems associated with fully nonlinear, possibly singular or degenerate elliptic equations. Our main result is a global H\"older estimate for solutions,…

Analysis of PDEs · Mathematics 2021-04-07 Isabeau Birindelli , Francoise Demengel , Fabiana Leoni

In this paper, to the best of our knowledge, we make the first attempt at studying the parametric semilinear elliptic eigenvalue problems with the parametric coefficient and some power-type nonlinearities. The parametric coefficient is…

Numerical Analysis · Mathematics 2024-05-02 Byeong-Ho Bahn

In this paper, we investigate the Dirichlet problem of Laplacian on complete Riemannian manifolds. By constructing new trial functions, we obtain a sharp upper bound of the gap of the consecutive eigenvalues in the sense of the order, which…

Differential Geometry · Mathematics 2016-12-21 Lingzhong Zeng

We revisit the eigenvalue problem of the Dirichlet Laplacian on bounded domains in complete Riemannian manifolds. By building on classical results like Li-Yau's and Yang's inequalities, we derive upper and lower bounds for eigenvalues. For…

Differential Geometry · Mathematics 2025-10-14 Daguang Chen , Qing-Ming Cheng

We deal with homogeneous Dirichlet and Neumann boundary-value problems for anisotropic elliptic operators of p-Laplace type. They emerge as Euler-Lagrange equations of integral functionals of the Calculus of Variations built upon possibly…

Analysis of PDEs · Mathematics 2025-10-28 Carlo Alberto Antonini , Andrea Cianchi

We consider perturbations of nonlinear eigenvalue problems driven by a nonhomogeneous differential operator plus an indefinite potential. We consider both sublinear and superlinear perturbations and we determine how the set of positive…

Analysis of PDEs · Mathematics 2018-11-13 Nikolaos S. Papageorgiou , Vicenţiu D. Rădulescu , Dušan D. Repovš

We establish sharp geometric Holder regularity estimates for Gradient for bounded solutions of a class of fully nonlinear elliptic equations with non-homogeneous degeneracy. Such regularity estimates simplify and generalize, to some extent,…

Analysis of PDEs · Mathematics 2020-08-13 G. C. Ricarte , J. V. Da Silva

Eigenvalue problems are critical to several fields of science and engineering. We present a novel unsupervised neural network for discovering eigenfunctions and eigenvalues for differential eigenvalue problems with solutions that…

Computational Physics · Physics 2020-10-13 Henry Jin , Marios Mattheakis , Pavlos Protopapas

We give inequalities relating the eigenvalues of the adjacency matrix and the Laplacian of a graph, and its minimum and maximum degrees. The results are applied to derive new conditions for quasi-randomness of graphs.

Combinatorics · Mathematics 2007-05-23 Vladimir Nikiforov

This paper is concerned with boundary regularity estimates in the homogenization of elliptic equations with rapidly oscillating and high-contrast coefficients. We establish uniform nontangential-maximal-function estimates for the Dirichlet,…

Analysis of PDEs · Mathematics 2021-05-28 Zhongwei Shen

For a Hermitian matrix $H \in \mathbb C^{n,n}$ and symmetric matrices $S_0, S_1,\ldots,S_k \in \mathbb C^{n,n}$, we consider the problem of computing the supremum of $\left\{ \frac{v^*Hv}{v^*v}:~v\in \mathbb C^{n}\setminus…

Numerical Analysis · Mathematics 2021-06-28 Anshul Prajapati , Punit Sharma

In this paper, we consider the principal eigenvalue problem for Hormander's laplacian on $R^n$. We also study a related semi-linear sub-elliptic equation in the whole $R^n$ and prove that under a suitable condition, we have infinite many…

Analysis of PDEs · Mathematics 2009-10-14 Li Ma , Dezhong Chen , Yang Yang

We present a new approach to compute selected eigenvalues and eigenvectors of the two-parameter eigenvalue problem. Our method requires computing generalized eigenvalue problems of the same size as the matrices of the initial two-parameter…

Numerical Analysis · Mathematics 2021-05-12 Henrik Eisenmann , Yuji Nakatsukasa

The eigenvalue problem for 3x3 octonionic Hermitian matrices contains some surprises, which we have reported elsewhere. In particular, the eigenvalues need not be real, there are 6 rather than 3 real eigenvalues, and the corresponding…

Rings and Algebras · Mathematics 2009-10-31 Tevian Dray , Corinne A. Manogue