arXiv research

Eigenvalue analogy explains item-based recommender system accuracy.

Estimates eigenvalue for Hermitian manifolds using curvature.

Two Riemannian manifolds are called eigenvalue equivalent when their sets of eigenvalues of the Laplace-Beltrami operator are equal (ignoring multiplicities). They are (primitive) length equivalent when the sets of lengths of their (primitive) closed geodesics are equal. We give a general construction of eigenvalue equ…

Study small eigenvalues of Toeplitz operators and their relation to Mabuchi geodesics.

The study sets lower bounds for eigenvalue sums of Laplacian on bounded domains and spheres.

Sharp Steklov eigenvalue estimates for differential forms on manifolds.

New eigenvalue problem for free boundary minimal surfaces in a ball.

The paper examines the rigidity of eigenvalues in shrinking Ricci solitons.

Eigenvalues of random hyperbolic surface covers converge to hyperbolic plane's.

Mathematicians decode geometric properties from eigenvalues over 112 years.

Paper derives second variation formula for eigenvalue functionals on surfaces.

We investigate various structures associated with the hyperbolic Markov and homological spectra of a pseudoAnosov map $φ$ on a surface. Each unstable eigenvalue of the action of $φ$ on first cohomolgy yields an eigen-cocycle that is transverse and holonomy invariant to the stable foliation $\mathcal{F}^s$ of $φ$. Each …

We generalise a theorem of Engman and Abreu--Freitas on the first invariant eigenvalue of non-negatively curved $S^{1}$-invariant metrics on $\mathbb{CP}^{1}$ to general toric Kähler metrics with non-negative scalar curvature. In particular, a simple upper bound of the first non-zero invariant eigenvalue for such metri…

Investigates financial portfolios using quantum system analogies and clustering properties.

We discuss asymptotic behavior of the eigenvalue distribution of the differential form Laplacian on a Riemannian foliated manifold when the metric on the ambient manifold is blown up in directions normal to the leaves (in the adiabatic limit). Motivated by analogies with semiclassical spectral asymptotics, we use ideas…

Study on metrics maximizing eigenvalues of Paneitz operator on 4-manifolds.

Our main result is that if a generic convex domain in $\R^n$ collapses to a domain in $\R^{n-1}$, then the difference between the first two Dirichlet eigenvalues of the Euclidean Laplacian, known as the fundamental gap, diverges. The boundary of the domain need not be smooth, merely Lipschitz continuous. To motivate th…

The paper bounds eigenvalues and integrals of eigenfunctions on hyperbolic manifolds.

In this note, we investigate upper bounds of the Neumann eigenvalue problem for the Laplacian of a bounded domain (with smooth boundary) in a given complete (not compact a priori) Riemannian manifold with Ricci bounded below . For this, we use test functions for the Rayleigh quotient subordinated to a family of open se…

We compare correlations and coherent structures in nuclei and financial markets. In the nuclear physics part we review giant resonances which can be interpreted as a coherent structure embedded in chaos. With similar methods we investigate the financial empirical correlation matrix of the DAX and Dow Jones. We will sho…

The paper reformulates Bakry-Émery curvature on graphs using eigenvalues.

We prove the Hijazi inequality, an estimate for Dirac eigenvalues, for complete manifolds of finite volume. Under some additional assumptions on the dimension and the scalar curvature, this inequality is also valid for elements of the essential spectrum. This allows to prove the conformal version of the Hijazi inequali…

We prove that, given any knot $γ$ in a compact 3-manifold M, there exists a Riemannian metric on M such that there is a complex-valued eigenfunction u of the Laplacian, corresponding to the first nontrivial eigenvalue, whose nodal set $u^{-1}(0)$ has a connected component given by $γ$. Higher dimensional analogs of thi…

Study of Steklov eigenvalues on degenerating conformal classes.

The study shows how discrete graphs can resemble hypercube structures under certain curvature conditions.

Negative curvature restricts the gap between the first and second eigenvalues of convex domains.

Let us fix a conformal class $[g_0]$ and a spin structure $σ$ on a compact manifold $M$. For any $g\in [g_0]$, let $λ^+_1(g)$ be the smallest positive eigenvalue of the Dirac operator $D$ on $(M,g,σ)$. In a previous paper we have shown that $$λ_{min}(M,g_0,σ):=\inf_{g\in [g_0]} λ_1^+(g)\vol(M,g)^{1/n}>0.$$ In the prese…

After introducing the sub-Riemannian geometry of the Heisenberg group Hn, n \geq 1, we recall some basics about hypersurfaces endowed with the H-perimeter measure and horizontal Green's formulas. Then, we describe a class of compact closed hypersurfaces of constant horizontal mean curvature called "Isoperimetric Profil…

Study shows isospectral Dirac metrics on 3-spheres are isometric.

This paper embeds surfaces in 3D spheres and balls with minimal area.

In this article we study the second variation of the energy functional associated to the Allen-Cahn equation on closed manifolds. Extending well known analogies between the gradient theory of phase transitions and the theory of minimal hypersurfaces, we prove the upper semicontinuity of the eigenvalues of the stability…

The paper solves conditions for prescribing scalar and Gauss curvatures on manifolds with zero first eigenvalue.

We consider smooth bounded surfaces with a smooth boundary and a prescribed background metric g_0. We now consider all metrics g conformal to g_0 which have a prescribed volume M. We now minimize the first eigenvalue of the Laplace operator of g over the metrics conformal to g_0 and having the prescribed volume. We sho…

We prove a Pohozaev type identity for non-linear eigenvalue equations of the Dirac operator on Riemannian spin manifolds with boundary. As an application, we obtain that the mean curvature H of a conformal immersion S^{n}-> R^{n+1} satisfies $\int \partial_X H=0$ where X is a conformal vector field on S^{n} and where t…

Study on Friedlander-Nadirashvili invariants on surfaces, especially non-orientable ones.

We show that in any harmonic space, the eigenvalue spectra of the Laplace operator on small geodesic spheres around a given point determine the norm $|\nabla R|$ of the covariant derivative of the Riemannian curvature tensor in that point. In particular, the spectra of small geodesic spheres in a harmonic space determi…

The study sharpens local Bernstein estimates for Laplace eigenfunctions on compact manifolds.

Let $G$ be a finite group with symmetric generating set $S$, and let $c = \max_{R > 0} |B(2R)|/|B(R)|$ be the doubling constant of the corresponding Cayley graph, where $B(R)$ denotes an $R$-ball in the word-metric with respect to $S$. We show that the multiplicity of the $k$th eigenvalue of the Laplacian on the Cayley…

The evolute of a smooth curve in an m-dimensional Euclidean space is the locus of centers of its osculating spheres, and the evolute of a spatial polygon is the polygon whose consecutive vertices are the centers of the spheres through the consecutive (m+1)-tuples of vertices of the original polygon. We study the iterat…

We refine some classical estimates in Seiberg-Witten theory, and discuss an application to the spectral geometry of three-manifolds. In particular, we show that on a rational homology three-sphere $Y$, for any Riemannian metric the first eigenvalue of the laplacian on coexact one-forms is bounded above explicitly in te…

Explains eigenvalue and generalized eigenvalue problems with examples.

We uncover scaling laws and statistical structure in complex datasets.

This article concerns upper bounds for $L^\infty$-norms of random approximate eigenfunctions of the Laplace operator on a compact aperiodic Riemannian manifold $(M,g).$ We study $f_λ$ chosen uniformly at random from the space of $L^2$-normalized linear combinations of Laplace eigenfunctions with eigenvalues in the inte…

The paper compares Steklov and Laplacian eigenvalues on graphs.

Paper finds bounds for Steklov eigenvalues on manifolds.

We prove that the Riemannian geometry of almost Kähler manifolds can be expressed in terms of the Poisson algebra of smooth functions on the manifold. Subsequently, Kähler-Poisson algebras are introduced, and it is shown that a corresponding purely algebraic theory of geometry and curvature can be developed. As an illu…

Bootstrap bounds on Einstein manifolds using semidefinite programming.

The paper explores inequalities between eigenvalues on Riemannian manifolds.