English

Second-order integrable Lagrangians and WDVV equations

Exactly Solvable and Integrable Systems 2021-05-12 v1 Mathematical Physics math.MP

Abstract

We investigate integrability of Euler-Lagrange equations associated with 2D second-order Lagrangians of the form \begin{equation*} \int f(u_{xx},u_{xy},u_{yy})\ dxdy. \end{equation*} By deriving integrability conditions for the Lagrangian density ff, examples of integrable Lagrangians expressible via elementary functions, Jacobi theta functions and dilogarithms are constructed. A link of second-order integrable Lagrangians to WDVV equations is established. Generalisations to 3D second-order integrable Lagrangians are also discussed.

Keywords

Cite

@article{arxiv.2007.03768,
  title  = {Second-order integrable Lagrangians and WDVV equations},
  author = {Evgeny V. Ferapontov and Maxim V. Pavlov and Lingling Xue},
  journal= {arXiv preprint arXiv:2007.03768},
  year   = {2021}
}
R2 v1 2026-06-23T16:56:02.495Z