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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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326395126 · May 202619922001200920172026
48 results for unitarily invariant

The hermitian analog of Aleksandrov's area measures of convex bodies is investigated. A characterization of those area measures which arise as the first variation of unitarily invariant valuations is established. General smooth area measures are shown to form a module over smooth valuations and the module of unitarily …

2012-07-27abs ↗pdf ↗

Researchers classify and decompose valuations on convex functions.

problem Classifying valuations on convex functions.
method Geometric decomposition of valuations, using properties of special subspaces and Monge-Ampère-type operators.
result Valuations decompose into subspaces defined by vanishing properties.

Given a positive and unitarily invariant Lagrangian L defined in the algebra of Hermitian matrices, and a fixed interval [a,b]R[a,b]\subset\mathbb R, we study the action defined in the Lie group of n×nn\times n unitary matrices U(n)\mathcal{U}(n) by S(α)=abL(α˙(t))dt, S(α)=\int_a^b L(\dotα(t))\,dt\,, where α:[a,b]U(n)α:[a,b]\to\mathcal{U}(n) is a …

2011-07-13abs ↗pdf ↗

We prove Fu's power series conjecture which relates the algebra of isometry invariant valuations on complex space forms to a formal power series from combinatorics which was introduced by Tutte. The nn-th coefficient of this series is the number of triangulations of a triangle with 3n3n internal edges; or the number o…

2020-01-10abs ↗pdf ↗

Study analyzes perturbations in singular subspaces under random noise.

problem Understanding singular vector and subspace changes in signal-plus-noise models.
method Generalized Davis-Kahan-Wedin theorem for any unitarily invariant norm, considering \ell_\infty and 2,\ell_{2,\infty} bounds.
result Fine-grained insights into singular vector and subspace perturbations, including \ell_\infty and 2,\ell_{2,\infty} bounds.

The local kinematic formulas on complex space forms induce the structure of a commutative algebra on the space CurvU(n)\mathrm{Curv}^{\mathrm{U}(n)*} of dual unitarily invariant curvature measures. Building on the recent results from integral geometry in complex space forms, we describe this algebra structure explicitly as a…

2017-02-07abs ↗pdf ↗

Let p: M -> B be a family of compact manifolds equipped with a unitarily flat vector bundle F -> M. We generalize Igusa's higher Franz-Reidemeister torsion τ(M/B;F) to the case that the fibre-wise cohomology H^*(M/B;F) -> B carries a parallel metric. If moreover M admits a fibre-wise Morse function, we compute the diff…

2003-05-20abs ↗pdf ↗

The paper compares two torsion invariants in complex vector bundles.

problem Comparing two torsion invariants in complex vector bundles.
method Constructing Bismut-Lott analytic torsion classes and showing they coincide with Igusa-Klein torsions.
result Bismut-Lott analytic torsion classes coincide with Igusa-Klein torsions for trivial flat line bundles.

Study on constant curvature immersions of surfaces into flag manifolds.

problem Investigate constant curvature immersions of Riemann surfaces into flag manifolds.
method Investigate pseudoholomorphic maps and invariant metrics on flag manifolds.
result Unitarily equivalent primitive immersions of the two-sphere into full flag manifolds have constant curvature under all invariant metrics.

Groups of importance in group theory have flexible stability properties.

problem Stability and flexibility of groups in geometric and combinatorial group theory.
method Establishing Kirchberg's Local Lifting Property and Lubotzky--Shalom's Property FD for specific groups.
result Groups like 33-manifold groups, limit groups, and certain one-relator groups are very flexibly stable.

We survey recent results in hermitian integral geometry, i.e. integral geometry on complex vector spaces and complex space forms. We study valuations and curvature measures on complex space forms and describe how the global and local kinematic formulas on such spaces were recently obtained. While the local and global k…

2016-12-05abs ↗pdf ↗

We prove the equality of the analytic torsion and the value at zero of a Ruelle dynamical zeta function associated with an acyclic unitarily flat vector bundle on a closed locally symmetric reductive manifold. This solves a conjecture of Fried. This article should be read in conjunction with an earlier paper by Moscovi…

2016-02-01abs ↗pdf ↗

In recent years, structured matrix recovery problems have gained considerable attention for its real world applications, such as recommender systems and computer vision. Much of the existing work has focused on matrices with low-rank structure, and limited progress has been made matrices with other types of structure. …

2016-04-12abs ↗pdf ↗

Study reflection symmetry and APS boundary conditions on a warped cylinder.

problem Analyzing reflection symmetry and APS boundary conditions for twisted Dirac operators on a finite warped cylinder.
method Examined reflection symmetry and APS boundary conditions for twisted Dirac operators on a finite warped cylinder, considering both fixed and varying holonomy.
result Reflection symmetry lifts to a unitary symmetry under specific conditions, and the spectral flow admits an RO(O(2))-valued decomposition for fixed holonomy.

We obtain upper bounds for the eigenvalues of the Schrödinger operator L=Δg+qL=Δ_g+q depending on integral quantities of the potential qq and a conformal invariant called the min-conformal volume. Moreover, when the Schrödinger operator LL is positive, integral quantities of qq which appear in upper bounds, can be repla…

2012-10-29abs ↗pdf ↗

Let Γ1Γ_1 and Γ2Γ_2 be Bieberbach groups contained in the full isometry group GG of Rn\mathbb{R}^n. We prove that if the compact flat manifolds Γ1\RnΓ_1\backslash\mathbb{R}^n and Γ2\RnΓ_2\backslash\mathbb{R}^n are strongly isospectral then the Bieberbach groups Γ1Γ_1 and Γ2Γ_2 are representation equivalent, that is, the rig…

2012-10-02abs ↗pdf ↗

Analytic torsion equals dynamical zeta function for certain bundles.

problem Equalities between analytic torsion and dynamical zeta functions.
method Analytic torsion and Ruelle dynamical zeta function for admissible twists.
result Generalization of previous results to admissible twists.

We establish the factorization of Dirac operators on Riemannian submersions of compact spinc^c manifolds in unbounded KK-theory. More precisely, we show that the Dirac operator on the total space of such a submersion is unitarily equivalent to the tensor sum of a family of Dirac operators with the Dirac operator on th…

2016-10-10abs ↗pdf ↗

We discuss inverse resonance scattering for the Laplacian on a rotationally symmetric manifold M=(0,)×YM = (0,\infty) \times Y whose rotation radius is constant outside some compact interval. The Laplacian on MM is unitarily equivalent to a direct sum of one-dimensional Schrödinger operators with compactly supported potenti…

2019-04-18abs ↗pdf ↗

Complex valued analytic torsion and dynamical zeta function studied on locally symmetric spaces.

problem Analyzing the Ruelle dynamical zeta function on locally symmetric spaces with flat vector bundles.
method Meromorphic extension and regularisation of the dynamical zeta function, relating it to the complex valued analytic torsion.
result The leading term of the dynamical zeta function at zero is related to the regularised determinant of the flat Laplacian.

Muons and random optimizers perform similarly, challenging geometric optimization theory.

problem Empirical success of Muon optimizer challenges geometric optimization theory.
method Introducing Freon and Kaon optimizers, demonstrating performance without precise geometric structure.
result Performance of optimizers is controlled by alignment and descent potential, not geometric structure.

Paper compares higher torsions and removes fiberwise Morse function assumption.

problem Comparing higher torsions from analytic and topological perspectives.
method Introduced fiberwise generalized Morse functions (GMFs) and excised neighborhoods around birth-death points.
result Established a generalized version of the higher Cheeger-Müller/Bismut-Zhang theorem.

Paper analyzes singular subspace estimation in noisy matrix models.

problem Estimating low-rank signals in noisy matrix data.
method Asymptotic distributional theory, extreme value theory, saddle point approximation, random matrix theory.
result Plug-in test statistic based on two-to-infinity norm has higher power for detecting structured alternatives.

This paper introduces SS-MAMP to address convergence issues in AMP algorithms.

problem Convergence issues in AMP algorithms for signal reconstruction.
method Proposes SS-MAMP algorithm framework for right-unitarily invariant sensing matrices and Lipschitz-continuous local processors.
result Covariance matrices of SS-MAMP are L-banded and convergent, ensuring optimal convergence.

In statistical relational learning, knowledge graph completion deals with automatically understanding the structure of large knowledge graphs---labeled directed graphs---and predicting missing relationships---labeled edges. State-of-the-art embedding models propose different trade-offs between modeling expressiveness, …

2017-02-22abs ↗pdf ↗

The aim of this work is to link the quasiconformal geometry of a Euclidean domain UU to the spectral properties of its Dirichlet integral $\D$, through the algebra of multipliers $\M(H^{1,2}(U))$ of the Sobolev space. In the main result we prove that a homeomorphism γ:Uγ(U)γ:U\toγ(U) between Euclidean domains, giving rise …

2019-09-05abs ↗pdf ↗

The horizontal Laplacian of a Riemannian submersion with totally geodesic fibers and an integrable horizontal distribution.

problem Studying spectral properties of the horizontal Laplacian
method Interpreting the horizontal Laplacian as a twisted Laplacian acting on a flat vector bundle
result The horizontal Laplacian is unitarily equivalent to a twisted Laplacian acting on the space of sections of a certain infinite-rank flat vector bundle over the base manifold

New curvature tensor and matrices for connection graphs derived from Bakry-Émery curvature.

problem Deriving Buser-type bounds on eigenvalues of connection Laplacians.
method Reformulation of Bakry-Émery curvature through curvature matrices and tensor representations.
result Extension of curvature matrices to connection graphs, addressing eigenfunction challenges.

Abstract invariant cannot be expressed using various slice-torus invariants.

problem Cannot express Iida-Taniguchi's slice-torus invariant using other known invariants.
method Analysis of various known invariants and their properties.
result Iida-Taniguchi's slice-torus invariant cannot be realized as a linear combination of other invariants.

The Kuperberg invariant is shown to be gauge invariant for certain framed 3-manifolds.

problem Exploring gauge invariance of the Kuperberg invariant for specific 3-manifolds.
method Using hyperbolic 3-manifolds and finite-dimensional Hopf algebras.
result First examples of gauge invariants of general finite-dimensional Hopf algebras via topological methods.

Paper introduces new invariant for pairs of immersions.

problem Understanding behavior of immersions through tangencies and triple points.
method Introduces J2+J^{2+}-invariant for oriented pairs of immersions, invariant under inverse tangencies and triple points.
result Invariant changes under direct tangencies but remains invariant under orientation change and inverse tangencies.

New invariant CWRCWR for alternating links is stronger than existing invariants.

problem Developing a stronger invariant for alternating links.
method Introducing CWRCWR invariant as an array of two-variable polynomials.
result The CWRCWR invariant is stronger than classical invariants like HOMFLYPT and Kauffman polynomials.

Defines knot concordance invariant using instanton homology and Donaldson invariants.

problem Knot concordance and its classification.
method Defines an invariant φ{\varphi} for knots in the 3-sphere using Donaldson invariants and Floer's instanton homology.
result The invariant φ{\varphi} coincides with a special case of an invariant defined by Froyshov.