New variational principle found for non-variational differential equations.
problem Non-variational differential equations without variational multipliers.
method Connecting functional forms with antiexact differential forms to identify obstructions.
result Formulation of variational problem for non-variational equations.
New variational principle found for PDEs with symmetries and conservation laws.
problem Finding variational principles for PDEs with symmetries and conservation laws.
method Proving existence of a variational principle for PDEs with symmetries and conservation laws.
result A differential equation with sufficient symmetries and conservation laws leads to a variational functional.
New method finds global Lagrangians for variational systems.
problem Constructing global variational principles for variational systems.
method Analyzing Lepage 2-forms and finding global Lagrangians for systems defined by homogeneous functions of degree \(c
eq 0, 1\).
result Locally variational systems defined by homogeneous functions of degree \(c
eq 0, 1\) are globally variational.
New approach to Lagrangian systems using intrinsic geometry.
problem Developing a new framework for Lagrangian systems.
method Direct reformulation of Hamiltonian formalism, introduction of spatial equation and spatial-gauge symmetry.
result Covariant and non-covariant canonical variational principles demonstrated for Maxwell equations.
Characterizes symplectic and variational operators for scalar evolution equations.
problem Understanding the cohomology spaces and operators for scalar evolution equations.
method Analyzes cohomology spaces and uses isomorphisms to characterize operators.
result Cohomology spaces and operator spaces are isomorphic for certain scalar evolution equations.
Study solves perpetual American option pricing using variational inequality and difference equation.
problem Pricing perpetual American options.
method Proved maximum principle and uniqueness for variational inequality, provided existence and uniqueness for difference equation, and proved convergence of difference equation solution to variational inequality solution.
result Solution to difference equation converges to viscosity solution of variational inequality, showing perpetual American option prices converge as maturity approaches infinity.
Schwarzian derivative connects to Euler-Lagrange equations in variational calculus.
problem Understanding the relationship between the Schwarzian derivative and variational equations.
method Analyzing the Schwarzian derivative as a first integral and Euler-Lagrange operator for specific variations.
result The Schwarzian derivative is both a first integral and the Euler-Lagrange operator for a certain class of variations.
Derives equations for systems with external forces using variational methods.
problem Deriving equations for systems subjected to external forces.
method Variational derivation of Euler-Poincaré equations using Poisson groupoid geometry.
result Derives variational error for numerical integrators of forced systems.
A variational principle is proposed for obtaining the Jacobi equations in systems admitting a Lagrangian description. The variational principle gives simultaneously the Lagrange equations of motion and the Jacobi variational equations for the system. The approach can be of help in finding constants of motion in the Jac…
Paper extends variational problem to spheres using control methods.
problem Extending classical variational problem to spheres.
method Variational and optimal control approaches.
result Established relation between Hamiltonian and Euler-Lagrange equations.
We consider variation of energy of the light-like particle in Riemann space-time, find lagrangian, canonical momenta and forces. Equations of the critical curve are obtained by the nonzero energy integral variation in accordance with principles of the calculus of variations in mechanics. This method is shown to not lea…
Elvet solves differential equations and variational problems with neural networks.
problem Solving complex differential and variational equations with arbitrary conditions.
method Machine learning, specifically neural networks, to represent and solve equations.
result Elvet can solve a wide range of differential and variational problems.
The paper explores variational principles for equations of maximal symmetry, providing new insights and results.
problem Exploring variational principles for equations of maximal symmetry.
method Study of variational and divergence symmetries for linear and nonlinear equations of maximal symmetry, providing first integrals in explicit form.
result Significantly different results and more general variational symmetry algebra for linear and nonlinear equations compared to previous studies.
A complete solution to the multiplier version of the inverse problem of the calculus of variations is given for a class of hyperbolic systems of second-order partial differential equations in two independent variables. The necessary and sufficient algebraic and differential conditions for the existence of a variational…
Geometrically describes Jacobi equations for field theories with dissipation.
problem Describing field theories with dissipation geometrically.
method Prolongation of the Lagrangian on a k-cosymplectic formulation to describe Jacobi equations and a modified Lagrangian for variational formulation.
result Variational formulation of field theories with dissipation.
We discuss a recently proposed variational principle for deriving the variational equations associated to any Lagrangian system. The principle gives simultaneously the Lagrange and the variational equations of the system. We define a new Lagrangian in an extended configuration space ---which we call D'Alambert's--- com…
New variational and multisymplectic formulations for soliton equations derived using the inverse map.
problem Formulating variational principles and multisymplectic formulations for Euler-Poincaré equations on the Virasoro-Bott group.
method Deriving new momentum map and multisymplectic formulation using the inverse map.
result New Clebsch momentum map with 2-cocycles for investigating soliton equations.
Study the stability of membranes using Helfrich energy and second variation formula.
problem Stability of membranes under various conditions.
method Developed and applied a second variation formula for the Helfrich energy for a class of surfaces.
result Studied the second variation of the area functional for a specific example.
Paper derives invariantised Euler-Lagrange equations for Herglotz problems.
problem Nonconservative Herglotz variational problems.
method Invariant calculus of variations and moving frames.
result Derivation of generalised Euler-Lagrange equations and conserved quantities.
The variational principle and the corresponding differential equation for geodesic circles in two dimensional (pseudo)-Riemannian space are being discovered. The relationship with the physical notion of uniformly accelerated relativistic particle is emphasized. The known form of spin-curvature interaction emerges due t…
Study magnetic geodesics on Kähler potentials using variational methods.
problem Understanding magnetic geodesics on Kähler potentials.
method Variational method for a generalized Landau-Hall functional.
result Magnetic geodesic equation and its relation to a perturbed complex Monge-Ampère equation.
The paper studies infinitesimal variations of submanifolds in Euclidean space.
problem Understanding infinitesimal variations of submanifolds of arbitrary dimension and codimension.
method Proving a system of three equations as integrability conditions for the differential equation determining infinitesimal variations.
result Established a Fundamental theorem for infinitesimal variations of submanifolds.
Variational calculus on a vector bundle E equipped with a structure of a general algebroid is developed, together with the corresponding analogs of Euler-Lagrange equations. Constrained systems are introduced in the variational and in the geometrical setting. The constrained Euler-Lagrange equations are derived for ana…
New geometric tools solve a top dynamics problem without a Lagrangian.
problem No globally defined Lagrangian for a relativistic top dynamics.
method Combined use of symmetry principles and inverse variational problem.
result No-existence of a globally defined Lagrangian for the top dynamics.
Proves Euler-Lagrange equations for complex functionals on Fréchet manifolds.
problem Variational calculus on Fréchet manifolds.
method Proves Euler-Lagrange equations for functionals on Fréchet manifolds.
result Validates Euler-Lagrange equations for specific functionals.
New statistical biharmonic maps derived from a variation problem.
problem Variation problem for mappings between statistical manifolds.
method Statistical biharmonic maps derived from the Euler-Lagrange equation.
result Improper affine hyperspheres induce examples of statistical biharmonic maps.
We establish new existence and non-existence results for positive solutions of the Einstein-scalar field Lichnerowicz equation on compact manifolds. This equation arises from the Hamiltonian constraint equation for the Einstein-scalar field system in general relativity. Our analysis introduces variational techniques, i…
Variationality of conformal geodesics fails in higher dimensions.
problem The variationality of conformal geodesics in higher dimensions.
method Analysis of conformal geodesics in three and higher dimensions.
result Variationality fails in both parametrized and un-parametrized conformal geodesics in higher dimensions.
Proposes variational Gaussian approximations for solving the Kushner equation.
problem Solving the Kushner equation for state estimation with observations.
method Tractable variational Gaussian approximations of proximal losses based on Wasserstein and Fisher metrics.
result The proposed method leads to a Gaussian flow consistent with Kalman-Bucy and Riccati flows.
In 3D, conformal geodesics are variational.
problem Whether conformal geodesics are variational in 3D.
method Demonstrated that the equation for unparametrized conformal geodesics is variational.
result Variationality of conformal geodesics in 3D.
New variational principles found for conformal geodesics.
problem Challenges in Lagrangian formulation for conformal geodesics.
method Enlarging the class of variations leads to a variational formulation with a third-order conformally invariant Lagrangian.
result Some integral curves of the fourth-order ODE system are spirals.
Solves inverse problem for Maxwell equations using vector fields.
problem Inverse problem for Maxwell equations in vacuum.
method Abstract theory of implicit differential equations over pre-symplectic manifolds.
result Provides solution for Maxwell equations using vector fields.
Derives equations for a Variational Bayes i-vector extractor.
problem Reduce overfitting or adapt i-vectors with limited data.
method Joint factor analysis and variational principal components.
result Derives equations for efficient i-vector extraction.
In this paper, we develop several related finite dimensional variational principles for discrete optimal transport (DOT), Minkowski type problems for convex polytopes and discrete Monge-Ampere equation (DMAE). A link between the discrete optimal transport, discrete Monge-Ampere equation and the power diagram in computa…
Study bounds the index of minimal submanifolds using energy measures and Yang-Mills-Higgs equations.
problem Bounding the index of codimension 2 minimal submanifolds.
method Second inner variation of energy, convergence of energy measures, and stress-energy tensors.
result Bound the Morse index of the submanifold by the index of critical points.
Paper constructs exact discrete Lagrangian for variational integrators.
problem Error analysis between exact and discrete trajectories.
method Construction of exact discrete Lagrangian in Lie groupoid and algebroid setting.
result Rigorous construction of exact discrete Lagrangian for variational integrators.
A large class of variational equations for geometric objects is studied. The results imply conformal monotonicity and Liouville theorems for steady, polytropic, ideal flow, and the regularity of weak solutions to generalized Yang-Mills and Born-Infeld systems.
The inverse problem of the calculus of variations asks whether a given system of partial differential equations (PDEs) admits a variational formulation. We show that the existence of a presymplectic form in the variational bicomplex, when horizontally closed on solutions, allows us to construct a variational formulatio…
Variational reduction simplifies Lagrangian systems with scaling symmetries.
problem Simplifying Lagrangian systems with scaling symmetries.
method Defining a variational reduction procedure for homogenous Lagrangian systems.
result Reconstructing trajectories from critical points of reduced variational principle.
Tackles variational problems with curvature and fractional Brezis-Nirenberg equations, overcoming lack of compactness.
problem Variational problems with curvature and fractional Brezis-Nirenberg equations.
method Refined techniques and Lyapunov-Schmidt method for ODE systems, blow-up analysis for elliptic equations.
result Existence and multiplicity of solutions with qualitative properties.
The paper studies variational functionals for submanifolds using the Lepage form.
problem Variational functionals for submanifolds in Grassmann fibrations.
method Introduces the fundamental Lepage form and uses it to study variations of submanifolds.
result Proves the first infinitesimal variation formula and Euler-Lagrange equations.
A financial swap reduces skew and fat tails in a portfolio's performance.
problem Managing skew and fat tails in portfolio performance.
method Used a third moment variation swap and partial differential equation approach.
result The hedged portfolio returns are more Gaussian-like with thin-tails.
Introduces a restricted Chen-Nagano variational principle for the Einstein-Hilbert functional.
problem Deriving critical metrics for the Einstein-Hilbert functional on compact Riemannian manifolds.
method Restricts the variational problem to an infinite-dimensional subspace.
result Derives a novel structural characterization of critical metrics.
Study on slow convergence in geometric variational problems.
problem Slow convergence of solutions in geometric variational problems.
method Identifying necessary conditions for slowly converging solutions and characterizing their convergence rate and direction.
result Characterization of the rate and direction of convergence for slowly converging solutions.
Paper approximates Gaussian process regression using variational methods.
problem Approximating Gaussian process regression efficiently.
method Represented as a stochastic differential equation, variational inference used for approximation.
result Approximations are as good as full Gaussian process regression.
The paper studies submanifolds of fixed degree with constraints on variations.
problem Variations of submanifolds of fixed degree in a graded manifold.
method Formulates area functional and associated variational vector fields, derives partial differential equations, and computes Euler-Lagrange equations.
result Mean curvature operator can be of third order when deformability condition holds.
A method to derive Lagrangians from field equations in metric-affine theories of gravity.
problem Deriving Lagrangians from field equations in metric-affine theories of gravity.
method Variational completion method to transform field equations into Euler-Lagrange equations and find a Lagrangian.
result Starting from metric equations, full metric equations and Lagrangian can be derived up to metric-independent terms.
The paper modifies Vafa-Witten equations on 4-manifolds for better solution estimates.
problem Constructing a priori estimates for solutions of Vafa-Witten equations on 4-manifolds.
method Introducing perturbation terms to the Vafa-Witten equations and proving transversality.
result The singularities of solutions can be removed, and moduli spaces constructed.