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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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82163245326 · Jun 202019922001200920172026
48 results for singular random Hamiltonian

Paper reviews algebraic research in machine learning theory.

problem Understanding phase transitions in machine learning models.
method Algebraic approaches in statistical mechanics.
result Algebraic methods are essential for analyzing machine learning models with singularities.

Study on contact Hamiltonian functions for singular contact structures.

problem Understanding infinitesimal contact transformations on singular contact structures.
method Showed injectivity and provided an explicit local formula for the inverse map.
result Explicit local formula for the inverse map when contact structure has singularities of the first type.

Constructs surfaces with conical singularities using variational methods.

problem Creating Hamiltonian Stationary Surfaces with specific singularities.
method Variational methods and convergence process similar to Ginzburg-Landau analysis.
result Obtained surfaces with prescribed conical singularities related to optimal Wente constants.

Algorithm classifies saddle-focus singularities in Hamiltonian systems.

problem Classifying nondegenerate saddle-focus singularities in integrable Hamiltonian systems.
method Developed an algorithm based on semi-local equivalence to represent singularities as almost direct products.
result Obtained complete lists of saddle-focus singularities of complexities 1, 2, and 3.

The paper classifies symplectic invariants of specific singularities in integrable Hamiltonian systems.

problem Classifying symplectic invariants of singularities in integrable Hamiltonian systems.
method Smooth CC^\infty symplectic classification of Lagrangian fibrations near singularities.
result Action variables form complete CC^\infty symplectic invariants for parabolic orbits and cuspidal tori.

The not-quite-Hamiltonian theory of singular reduction and reconstruction is described. This includes the notions of both regular and collective Hamiltonian reduction and reconstruction.

2014-12-03abs ↗pdf ↗

We show a natural relation between the monodromy formula for focus-focus singularities of integrable Hamiltonian systems and a formula of Duistermaat-Heckman, and extend the main results of our previous note on focus-focus singularities ($\bbS^1$-action, monodromy, and topological classification) to the degenerate case…

2001-10-14abs ↗pdf ↗

Reduces symplectic manifolds with singularities for quantum reduction.

problem Quantization commutes with reduction for singular symplectic manifolds.
method Reduction theory for bmb^m-symplectic manifolds and folded symplectic manifolds under general symmetries.
result New constructions of (singular) quasi-Hamiltonian spaces via reduction and fusion product.

Proves Arnold conjecture for singular symplectic manifolds using novel techniques.

problem Hamiltonian dynamics on singular symplectic manifolds.
method Introducing smooth symplectic forms to singular symplectic structures under mild conditions, using Floer homology.
result Proves a lower bound on the number of 1-periodic Hamiltonian orbits for b2mb^{2m}-symplectic manifolds.

In this paper, we develop results in the direction of an analogue of Sjamaar and Lerman's singular reduction of Hamiltonian symplectic manifolds in the context of reduction of Hamiltonian generalized complex manifolds (in the sense of Lin and Tolman). Specifically, we prove that if a compact Lie group acts on a general…

2010-03-09abs ↗pdf ↗

HF-opt uses Hamiltonian dynamics to optimize functions, achieving accelerated rates with randomized integration time.

problem Optimizing functions efficiently and accelerating convergence rates.
method Randomized Hamiltonian flow (RHF) with accelerated convergence rates.
result RHGD achieves accelerated convergence rates similar to Nesterov's AGD.

Study on singularities of Lagrangian immersions with applications in Floer theory.

problem Understanding singularities of Lagrangian immersions.
method Applying Hamiltonian isotopy in the Weinstein tubular neighbourhood to express singular points as fold points with cusp points.
result Local expression of singular points of Lagrangian immersions as fold points with cusp points.

Symplectic classification for a specific type of singularity in integrable systems.

problem Symplectic classification of integrable systems near singular points of type AnA_n.
method Real-analytic symplectic normal forms and classification of Lagrangian foliations.
result All integrable systems are symplectically equivalent near singular points of this type.

New geometric structures that relate the lagrangian and hamiltonian formalisms defined upon a singular lagrangian are presented. Several vector fields are constructed in velocity space that give new and precise answers to several topics like the projectability of a vector field to a hamiltonian vector field, the comput…

2000-09-29abs ↗pdf ↗

We generalize the Weinstein-Moser theorem on the existence of nonlinear normal modes near an equilibrium in a Hamiltonian system to a theorem on the existence of relative perodic orbits near a relative equilibrium in a Hamiltonian system with continuous symmetries. In particular we prove that under appropriate hypothes…

1999-01-22abs ↗pdf ↗

We give a topological and geometrical description of focus-focus singularities of integrable Hamiltonian systems. In particular, we explain why the monodromy around these singularities is non-trivial, a result obtained before by J.J. Duistermaat and others for some concrete systems.

2001-10-14abs ↗pdf ↗

The paper proves optimal smoothness for certain Lagrangian graphs with specific Hölder continuity.

problem Optimal regularity for Hölder continuous Hamiltonian stationary Lagrangian graphs.
method Establishing smoothness conditions based on Hölder exponent and Lagrangian phase properties.
result Smoothness of graphs is achieved when Hölder exponent is strictly greater than 1/3 and Lagrangian phase is supercritical.

This paper extends the evolution operator to contact mechanics, linking Lagrangian and Hamiltonian formulations.

problem Translating the evolution operator to contact mechanics for mechanical systems with dissipation.
method Using the evolution operator K to connect Lagrangian and Hamiltonian formalisms in contact mechanics.
result The evolution operator provides a geometric description of evolution equations and relates constraints.

Generalizes isomonodromic-isospectral correspondence for twisted connections.

problem Extending isomonodromic-isospectral correspondence to twisted cases.
method Construction of isospectral approach for Painlevé I hierarchy, two maps linking isomonodromic and isospectral Hamiltonians, and apparent singularities to isospectral coordinates.
result Established a correspondence between isomonodromic and isospectral systems for twisted connections.

Study plane curve singularities to determine vanishing cycles and monodromy groups.

problem Understanding vanishing cycles and monodromy groups for plane curve singularities.
method Intrinsic description of geometric monodromy group, easy criterion for vanishing cycles, canonical framing.
result Monodromy groups are injective for singularities with Milnor fiber of genus at least 7.

We classify linear Nambu structures (which are generalized Poisson structures in Hamiltonian dynamics and which give rise to integrable differential forms and singular foliations), then give a linearization for Nambu structures anf integrable differential forms near a nondegenerate singular point.

1997-07-10abs ↗pdf ↗

New methods improve efficiency of sampling algorithms for complex systems.

problem Efficiently sampling from complex, high-dimensional probability distributions.
method Randomized Runge-Kutta-Nyström methods tailored for Hamiltonian flows.
result Quantitative 5/25/2-order L2L^2-accuracy in approximating Hamiltonian flows.

We prove a criterion for stability of relative equilibria in symmetric Hamiltonian systems at singular points of the momentum map. This generalizes a theorem of G.W. Patrick. The method of the proof is also useful in studying the bifurcation of relative equilibria.

1997-06-12abs ↗pdf ↗

The paper explores the connection between Poisson-Lie structures and invariant volume forms in Hamiltonian dynamics.

problem Understanding the relationship between Poisson-Lie structures and invariant volume forms in Hamiltonian systems.
method Analyzing the existence and preservation of invariant volume forms under Hamiltonian vector fields on Poisson-Lie groups.
result A unimodular Poisson-Lie structure ensures the preservation of a multiple of any left-invariant volume, and the existence of a preserving volume form implies unimodularity.

The paper extends a theorem about momentum maps to singular symplectic spaces.

problem Extending a theorem about momentum maps to singular symplectic spaces.
method Using integral affine stratification and equivariant locally trivial fibrations, the paper extends the linear variation theorem to singular values of the momentum map.
result Cohomology classes of symplectic forms on reduced spaces vary linearly within strata.

The paper develops a theory linking Hamiltonian and quasi-Hamiltonian manifolds.

problem Understanding the deformation of Hamiltonian quasi-Poisson manifolds to Hamiltonian Poisson manifolds.
method Introduces a generalized Hamiltonian deformation theory and constructs a topological quantum field theory.
result Shows that the imploded cross section of the double $D(G)_\imp$ deforms to the implosion of the cotangent bundle $T^*G_\imp$.

HMC improves Gaussian sampling efficiency with long, random steps.

problem Efficiently sampling from high-dimensional Gaussian distributions.
method Hamiltonian Monte Carlo with long and random integration times.
result HMC achieves ε\varepsilon-closeness in total variation distance with O~(κd1/4log(1/ε))\widetilde{O}(\sqrt{\kappa} d^{1/4} \log(1/\varepsilon)) gradient queries.

Consider a compact prequantizable symplectic manifold M on which a compact Lie group G acts in a Hamiltonian fashion. The ``quantization commutes with reduction'' theorem asserts that the G-invariant part of the equivariant index of M is equal to the Riemann-Roch number of the symplectic quotient of M, provided the quo…

1997-07-30abs ↗pdf ↗

Defines new canonical lifts for field theories, analyzing Klein-Gordon, Polyakov string, and Einstein-Cartan gravity.

problem Analyzing natural Noether symmetries and conserved quantities in field theories.
method Defining canonical lifts to study field theories and applying Noether's theorem.
result New geometrical interpretation of Virasoro constraint in string theory.

Approximate Bayesian computation (ABC) is a powerful and elegant framework for performing inference in simulation-based models. However, due to the difficulty in scaling likelihood estimates, ABC remains useful for relatively low-dimensional problems. We introduce Hamiltonian ABC (HABC), a set of likelihood-free algori…

2015-03-06abs ↗pdf ↗

We study Hamiltonian dynamics of gradient Kaehler-Ricci solitons that arise as limits of dilations of singularities of the Ricci flow on compact Kaehler manifolds. Our main result is that the underlying spaces of such gradient solitons must be Stein manifolds. Moreover, on all most all energy surfaces of the potential …

1998-07-02abs ↗pdf ↗

Simulating the time-evolution of quantum mechanical systems is BQP-hard and expected to be one of the foremost applications of quantum computers. We consider classical algorithms for the approximation of Hamiltonian dynamics using subsampling methods from randomized numerical linear algebra. We derive a simulation tech…

2018-04-06abs ↗pdf ↗

New algorithm speeds up MCMC for complex distributions.

problem Efficient sampling from complex, high-dimensional distributions.
method Numerical Generalized Randomized Hamiltonian Monte Carlo with state-dependent event rates.
result Approximates Hamiltonian trajectories for robust sampling.

New method samples from piecewise smooth distributions using Hamiltonian Monte Carlo.

problem Sampling from distributions with discontinuous gradients.
method Generalized Randomized Hamiltonian Monte Carlo (GRHMC) for piecewise smooth targets.
result GRHMC processes sample from piecewise smooth target distributions with the desired distribution as the invariant distribution.

The Rusk-Skinner formalism was developed in order to give a geometrical unified formalism for describing mechanical systems. It incorporates all the characteristics of Lagrangian and Hamiltonian descriptions of these systems (including dynamical equations and solutions, constraints, Legendre map, evolution operators, e…

2002-12-02abs ↗pdf ↗

Given any embedded Lagrangian on a four dimensional compact Calabi-Yau, we find another Lagrangian in the same Hamiltonian isotopy class which develops a finite time singularity under mean curvature flow. This contradicts a weaker version of the Thomas-Yau conjecture regarding long time existence and convergence of Lag…

2010-09-06abs ↗pdf ↗