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arXiv research

A locally-built, LLM-digested index of recent arXiv papers in quant finance, geometry/topology, and statistical ML — keyword search served straight from SQLite on this machine.

168,695 papers · 148 categories

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4895143190 · May 202619922001200920172026
48 results for positive spectrum

ManifoldFlow relaxes fixed-spectrum Stiefel layers to learn a positive spectrum.

problem Fixed-spectrum Stiefel layers impose rigid spectral constraints.
method Introduces ManifoldFlow, a relaxation that learns a positive spectrum while keeping the basis on the Stiefel manifold.
result Learnable SPD spectrum improves performance in various settings.

We show existence of solutions to the Poisson equation on Riemannian manifolds with positive essential spectrum, assuming a sharp pointwise decay on the source function. In particular we can allow the Ricci curvature to be unbounded from below. In comparison with previous works, we can deal with a more general setting …

2018-03-27abs ↗pdf ↗

We study the spectrum of complete noncompact manifolds with bounded curvature and positive injectivity radius. We give general conditions which imply that their essential spectrum has an arbitrarily large finite number of gaps. In particular, for any noncompact covering of a compact manifold, there is a metric on the b…

2015-10-16abs ↗pdf ↗

We show how a suitably twisted Spin-cobordism spectrum connects to the question of existence of metrics of positive scalar curvature on closed, smooth manifolds by building on fundamental work of Gromov, Lawson, Rosenberg, Stolz and others. We then investigate this parametrised spectrum, compute its mod 2mod~2-cohomology …

2013-11-13abs ↗pdf ↗

Sharp bounds and parabolicity results for 3-manifolds with scalar curvature.

problem Understanding the spectrum and parabolicity of 3-manifolds with scalar curvature constraints.
method Established global results for complete three-dimensional manifolds under a topological assumption.
result Sharp upper bounds for the bottom spectrum and parabolicity results for manifolds with scalar curvature lower bounds.

Study approximate marked length spectrum rigidity in non-positively curved groups.

problem Approximate rigidity of marked length spectra in non-positively curved groups.
method Compare marked length spectra of isometric actions of groups with non-positively curved features.
result Supremum of quotient of marked length spectra is approximately determined by restricted spectra.

Formula derived for Laplace-Beltrami spectrum on homogeneous spaces.

problem Calculating the spectrum of the Laplace-Beltrami operator on homogeneous spaces.
method Formula derivation based on eigenvalues of a generalized Casimir operator and spherical representations.
result First detailed computation and investigation of the spectrum for a family of metrics on the Aloff-Wallach manifold.

Study magnetic potentials on Anosov manifolds using spectral data.

problem Recover magnetic potentials from spectral data on Anosov manifolds.
method Utilize principal wave trace invariants and magnetic Schrödinger operator.
result Spectral data uniquely determines magnetic and electric potentials on Anosov manifolds.

Study the energy spectrum of metrics on surfaces and its relation to simple length spectrum.

problem Relate the energy spectrum to the simple length spectrum of metrics on surfaces.
method Analyze the energy spectrum of metrics on surfaces and their Teichmüller spaces, considering homotopy conditions.
result The energy spectrum determines the simple length spectrum under certain conditions.

Study Dirichlet-to-Neumann maps on manifolds, focusing on covering and total spaces.

problem Understanding the Steklov spectrum of covering and total spaces.
method Analyzing Dirichlet-to-Neumann maps on Riemannian manifolds with boundary and bounded geometry.
result Existence and properties of the bottom of the Dirichlet spectrum on covering and total spaces.

In all dimensions, we prove that the marked length spectrum of a Riemannian manifold (M,g)(M,g) with Anosov geodesic flow and non-positive curvature locally determines the metric in the sense that two close enough metrics with the same marked length spectrum are isometric. In addition, we provide a completely new stabilit…

2018-06-11abs ↗pdf ↗

Geometric characterization of sub-Riemannian geodesics on frame bundles.

problem Characterize sub-Riemannian geodesics on frame bundles of 3-manifolds.
method Lie theoretical description, geometric characterization, complex length spectrum computation.
result Sub-Riemannian metrics on frame bundles of isospectral manifolds are length isospectral.

An adapted version of the proof (due to A. Weil) of the well-known de Rham Theorem allows us to compare uniformly the spectrum of the Hodge Laplacian acting on differential forms (on a compact Riemannian manifold) to the spectrum of the combinatorial Laplacian acting on cochains associated to an open cover (made of bal…

2006-09-21abs ↗pdf ↗

Consider a quantum particle trapped between a curved layer of constant width built over a complete, non-compact, C2\mathcal C^2 smooth surface embedded in R3\mathbb{R}^3. We assume that the surface is asymptotically flat in the sense that the second fundamental form vanishes at infinity, and that the surface is not tot…

2011-10-31abs ↗pdf ↗

The classical inverse problem of recovering a simply connected smooth planar domain from the Steklov spectrum \cite{E} is equivalent to the problem of recovering, up to a conformal equivalence, a positive function aC(S)a\in C^\infty({\mathbb S}) on the unit circle S={eiθ}{\mathbb S}=\{e^{iθ}\} from the eigenvalue spectrum of t…

2014-04-08abs ↗pdf ↗

The study of spectral-tightness in Riemannian manifolds and its topological implications.

problem Understanding the spectral properties of Riemannian manifolds and their coverings.
method Analyzing the fundamental group and the Euclidean local de Rham factor to characterize spectral-tightness.
result Spectral-tightness is a topological property of the fundamental group, and it can be characterized by the dimension of the Euclidean local de Rham factor.

We establish a uniform comparison between the spectrum of the rough Laplacian (acting on sections of a vector bundle of complex rank one or of harmonic curvature) with the spectrum of a discrete operator (a generalization of a discrete magnetic Laplacian added with a potential) acting on a finite dimensional space comi…

2006-09-21abs ↗pdf ↗

Infinite volume requires no atoms at the bottom of the spectrum for certain groups.

problem Determining conditions for infinite volume in certain algebraic groups.
method Analyzing the spectral properties of Laplace operators on symmetric spaces.
result The bottom of the L2L^2-spectrum being an atom is necessary and sufficient for finite volume.

We study various covering spectra for complete noncompact length spaces with universal covers (including Riemannian manifolds and the pointed Gromov Hausdorff limits of Riemannian manifolds with lower bounds on their Ricci curvature). We relate the covering spectrum to the (marked) shift spectrum of such a space. We de…

2012-11-30abs ↗pdf ↗

The study examines arithmetic orbifolds and their length spectra, proving uniform discreteness and linear dependence of geodesic lengths.

problem Uniform discreteness and linear dependence of geodesic lengths in arithmetic orbifolds.
method Analyzes Salem numbers and Lie groups to prove uniform discreteness, and uses geometric properties to show linear dependence of geodesic lengths.
result Existence of a positive constant δ(X) such that squares of lengths of closed geodesics shorter than δ must be pairwise linearly dependent over Q.

Motivated by the theory of quantum waveguides, we investigate the spectrum of the Laplacian, subject to Dirichlet boundary conditions, in a curved strip of constant width that is defined as a tubular neighbourhood of an infinite curve in a two-dimensional Riemannian manifold. Under the assumption that the strip is asym…

2002-04-26abs ↗pdf ↗

Krein's formula for conic Laplacians on compact Riemann surfaces

problem Establishing Krein's formula for self-adjoint extensions of conic Laplacians on compact Riemann surfaces
method Using finite-dimensional symplectic space of critical asymptotic boundary data
result Deriving a trace identity for the resolvent difference and proving a comparison formula for the positive-spectrum zeta determinants

The paper identifies magnetic ground states and their role in determining the conformal class of a surface.

problem Understanding the magnetic ground states and their relation to the conformal class of a surface.
method Analyzing the magnetic Laplacian and its eigenvalues on a Riemannian surface.
result The ground state spectrum uniquely determines the volume and conformal class of the metric.

The Hodge spectra can distinguish orbifolds from manifolds, especially in low dimensions.

problem Distinguishing orbifolds from manifolds using Hodge spectra.
method Computing heat invariants of Hodge Laplacians on pp-forms.
result The Hodge spectra, particularly the 00- and 11-spectra, can distinguish orbifolds from manifolds in low dimensions.

The paper studies harmonic 1-forms on specific metric measure spaces.

problem Analyzing harmonic 1-forms on non-compact smooth metric measure spaces.
method Establishing splitting and vanishing theorems for LfpL_f^p harmonic 1-forms under curvature conditions.
result Two new theorems for LfpL_f^p harmonic 1-forms are proven.

Study compares spectral properties of a specific tensor in geometry.

problem Comparing spectral properties of a specific tensor in geometry.
method Diameter and global weighted volume comparison with a positive lower bound on the NN-Bakry-Emery Ricci tensor.
result Established diameter and volume comparisons for tensors with positive lower bounds.

We study the spectral properties of curl, a linear differential operator of first order acting on differential forms of appropriate degree on an odd-dimensional closed oriented Riemannian manifold. In three dimensions its eigenvalues are the electromagnetic oscillation frequencies in vacuum without external sources. In…

2017-02-07abs ↗pdf ↗