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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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48 results for Matrix equations

In this paper, we study the Poisson equation and heat equation in a model matrix geometry MnM_n. Our main results are about the Poisson equation and global behavior of the heat equation on MnM_n. We can show that if c0c_0 is the initial positive definite matrix in MnM_n, then c(t)c(t) exists for all time and is positive …

2013-11-21abs ↗pdf ↗

Solutions to a quadratic matrix equation are linked to strongly regular graphs and multiplicative characters.

problem Solving a specific quadratic matrix equation in Riemannian geometry.
method Constructing nonzero solutions using group rings and multiplicative characters of finite fields.
result Solutions relate to strongly regular graphs and multiplicative characters of finite fields.

New method solves robust matrix completion using nonlinear equations.

problem Recover low rank and sparse matrices from incomplete observations.
method Transforms problem into solving a system of nonlinear equations, then uses the alternative direction method.
result Algorithm converges linearly to the true solution under proper assumptions.

Derives matrix Harnack inequalities for semilinear heat equations on manifolds.

problem Bounding solutions of semilinear heat equations on manifolds with geometric constraints.
method Applies Li-Yau estimates to derive Harnack inequalities for positive solutions.
result Derives matrix Harnack inequalities for positive solutions of semilinear heat equations.

Improved heat equation estimates without gradient curvature assumption.

problem Improving Hamilton's matrix Harnack estimate for heat equation without gradient curvature assumption.
method New ingredients include a sharp Li-Yau estimate, a suitable vector field construction, and integral arguments.
result Removed the gradient curvature assumption in Hamilton's estimate for heat equation.

Geometrodynamics derived from Riemannian manifolds using geospin matrix.

problem Formulating dynamics on Riemannian manifolds using Cartan structural equations.
method Introducing four real dynamical variables and applying them to Cartan structural equations.
result Rewritten Cartan structural equations in a real geometrodynamical form.

New approach to analyze matrix denoising using gradient flow and fixed point equations.

problem Positive semi-definite matrix denoising in extensive-rank and high-dimensional settings.
method Gradient flow and fixed point equations derived from linear pencil techniques of random matrix theory.
result Continuous phase transitions in the extensive-rank and high-dimensional regime.

Recovering matrix valued potentials from wave equation data on stationary spacetimes.

problem Recovering a time-dependent matrix valued potential from wave equation data.
method Reduction to non-Abelian light ray transform and study of the transform.
result Sufficient conditions for solving the inverse problem on stationary spacetimes.

We derive an interpolation version of constrained matrix Li-Yau-Hamilton estimate on Kähler manifolds. As a result, we first get a constrained matrix Li-Yau-Hamilton estimate for heat equation on a Kähler manifold with fixed Kähler metric. Secondly, we get a corresponding estimate for forward conjugate heat equation on…

2014-07-01abs ↗pdf ↗

Since Li and Yau obtained the gradient estimate for the heat equation, related estimates have been extensively studied. With additional curvature assumptions, matrix estimates that generalize such estimates have been discovered for various time-dependent settings, including the heat equation on a Kähler manifold, Ricci…

2017-04-25abs ↗pdf ↗

New Hessian estimates for heat equations on manifolds.

problem Estimating Hessian matrices for heat-type equations on Riemannian manifolds.
method Using Bismut-Stroock Hessian formula, with explicit coefficients and delay/growth rate functions.
result Novel backward weak Harnack inequality and precise pointwise Hessian estimates for eigenfunctions.

A new matrix concentration inequality for random products of matrices.

problem Understanding the behavior of random matrix products under bounded independent positive semidefinite matrices.
method Developed a non-asymptotic concentration inequality for the product of matrices.
result The inequality provides a bound on the deviation of the matrix product from its expected value.

We prove constrained trace, matrix and constrained matrix Harnack inequalities for the nonlinear heat equation ωt=Δω+aωlnωω_t=Δω+aω\ln ω on closed manifolds. We also derive a new interpolated Harnack inequality for the equation ωt=Δωωlnω+εRωω_t=Δω-ω\lnω+\varepsilon Rω on closed surfaces under the ε\varepsilon-Ricci flow. Finally we prove…

2018-03-28abs ↗pdf ↗

In this paper we are concerned with the matrix Li-Yau-Hamilton estimates for nonlinear heat equations. Firstly, we derive such estimate on a Kähler manifold with a fixed Kähler metric. Then we consider the estimate on Kähler manifolds with Kähler metrics evolving under the rescaled Kähler-Ricci flow. Both of the estima…

2019-11-01abs ↗pdf ↗

Paper proves estimates for heat and conjugate heat equations under Ricci flow, leading to monotonicity of parabolic frequencies.

problem Establishing estimates for heat and conjugate heat equations under Ricci flow.
method Proving matrix Li-Yau-Hamilton estimates for positive solutions to the heat and conjugate heat equations coupled with Ricci flow.
result Monotonicity of parabolic frequencies established up to correction factors.

Paper proposes a new approach to optimal transport for vector and matrix densities.

problem Optimal transport for vector and matrix densities with positivity and action transitivity constraints.
method Gauge-theoretic approach using semi-direct product groups of diffeomorphisms and gauge transformations.
result Bures-type metrics on semi-direct product groups relate to Wasserstein-type metrics on vector and matrix densities via Riemannian submersions.

Graphical notation simplifies complex polynomial constraints in linear models.

problem Complex polynomial constraints in linear structural equation models are impractical.
method Developed a graphical notation to represent these constraints.
result The graphical notation simplifies the representation of many polynomial constraints.

Study on Langevin dynamics for recovering planted signals in spiked matrix models.

problem Recovering a planted signal in spiked matrix models.
method Path-wise characterization of overlap using integro-differential equations and explicit formula derivation.
result Sharp phase transition in limiting overlap: positive in one regime, zero in another due to injected noise.

We consider cones over manifolds admitting real Killing spinors and instanton equations on connections on vector bundles over these manifolds. Such cones are manifolds with special (reduced) holonomy. We generalize the scalar ansatz for a connection proposed by Harland and Nolle in such a way that instantons are parame…

2012-03-12abs ↗pdf ↗

Nous montrons que les équations du repère mobile des surfaces de Bonnet conduisent à une paire de Lax matricielle isomonodromique d'ordre deux pour la sixième équation de Painlevé. We show that the moving frame equations of Bonnet surfaces can be extrapolated to a second order, isomonodromic matrix Lax pair of the sixt…

2016-07-05abs ↗pdf ↗

Researchers compute A-polynomials of manifolds using symplectic properties and cluster algebras.

problem Computing A-polynomials of infinite families of knots and related manifolds is difficult.
method Starting with a triangulation, they use symplectic properties of the Neumann-Zagier matrix to simplify the computation.
result The defining equations of A-polynomials of manifolds obtained by Dehn filling are Ptolemy equations.

New integrable matrix PDEs derived from Frölicher-Nijenhuis brackets.

problem Developing integrable systems from tensor field properties.
method Using Frölicher-Nijenhuis brackets to generate bi-differential graded algebras and PDE systems.
result New integrable nonlinear matrix PDEs and systems are derived.

New bounds for private matrix approximation using Gaussian noise and Dyson Brownian Motion.

problem Private approximation of symmetric matrices with Gaussian noise.
method Viewing Gaussian noise as Dyson Brownian Motion to track eigenvalue and eigenvector evolution.
result Improved bounds on Frobenius-distance utility for private matrix approximation.

Computes isotropy subgroups of orthogonal matrices acting on Hermitian matrices.

problem Computing isotropy subgroups of orthogonal matrices acting on Hermitian matrices.
method Algorithm for solving a matrix equation to compute isotropy subgroups.
result Computed isotropy subgroups of orthogonal matrices acting on Hermitian matrices.

Paper connects algebraic and analytic methods for braid group representations.

problem Constructing representations of braid groups using algebraic and analytic approaches.
method Katz-Long-Moody construction and multiplicative middle convolution for KZ-type equations.
result Multiplicative middle convolution preserves unitarity and provides an algorithm to determine the signature of a Hermitian matrix.

New method finds efficient low-rank neural networks during training.

problem High memory and computational demands of neural networks.
method Restricts weight matrices to a low-rank manifold and updates low-rank factors.
result Significantly reduced time and memory resources required for training and evaluation.

Particles representing tokens cluster in Transformers, influenced by initial tokens and matrix spectrum.

problem Understanding the geometry of learned representations in Transformers.
method Viewing Transformers as particle systems, applying dynamical systems and partial differential equations.
result Particles cluster towards limiting objects, confirming context-awareness and the emergence of leaders.

Derives a Hamiltonian model for 3D axially symmetric magnetohydrodynamics.

problem Modeling of 3D axially symmetric magnetohydrodynamics.
method Hamiltonian formulation and matrix discretization.
result First discrete model for 3D magnetohydrodynamics compatible with underlying Lie-Poisson structure.

Study on neural network initialization with shaped infinite depth-and-width networks.

problem Understanding the distribution of random covariance matrices in shaped infinite-depth-and-width networks.
method Introduced the Neural Covariance SDE to model the distribution of the random covariance matrix.
result Identified the precise scaling of the activation function necessary for a non-trivial limit.

Traditional models of macroeconomic dynamics are fundamentally incorrect. The reason lies in a misunderstanding of peculiarities of the analysis of infinitesimal quantities. However, even those types of solutions that are envisaged by the above-mentioned models are nonrepresentative in the sense of the reflection of re…

2008-04-23abs ↗pdf ↗

In this article, we show that solving the system of linear equations by manipulating the kernel and the range space is equivalent to solving the problem of least squares error approximation. This establishes the ground for a gradient-free learning search when the system can be expressed in the form of a linear matrix e…

2018-10-27abs ↗pdf ↗

Dynamics of four-dimensional massless fields of all spins is formulated in the Siegel space of complex 4×44\times 4 symmetric matrices. It is shown that the unfolded equations of free massless fields, that have a form of multidimensional Schrodinger equations, naturally distinguish between positive- and negative-frequen…

2008-01-15abs ↗pdf ↗