Degree growth of lattice equations defined on a 3 × 3 stencil




Hietarinta, Jarmo

PublisherEpisciences

2024

 Open Communications in Nonlinear Mathematical Physics

Open Communications in Nonlinear Mathematical Physics

2024

Special Issue 1

1

19

2802-9356

DOIhttps://doi.org/10.46298/ocnmp.11589

https://doi.org/10.46298/ocnmp.11589

https://research.utu.fi/converis/portal/detail/Publication/484743359



We study complexity in terms of degree growth of one-component lattice equations defined on a 3 × 3 stencil. The equations include two in Hirota bilinear form and the Boussinesq equations of regular, modified and Schwarzian type. Initial values are given on a staircase or on a corner configuration and depend linearly or rationally on a special variable, for example fn,m = αn,m z + βn,m, in which case we count the degree in z of the iterates. Known integrable cases have linear growth if only one initial values contains z, and quadratic growth if all initial values contain z. Even a small deformation of an integrable equation changes the degree growth from polynomial to exponential, because the deformation will change factorization properties and thereby prevent cancellations.




Exactly Solvable and Integrable SystemsNonlinear Sciences

Last updated on 17/02/2025 01:52:46 PM