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arXiv · 1407.1258

Symmetries and conservation laws of the generalized Krichever-Novikov equation

Abstract

A computational classification of contact symmetries and higher-order local symmetries that do not commute with $t,x$, as well as local conserved densities that are not invariant under $t,x$ is carried out for a generalized version of the Krichever-Novikov equation. Several new results are obtained. First, the Krichever-Novikov equation is explicitly shown to have a local conserved density that contains $t,x$. Second, apart from the dilational point symmetries known for special cases of the Krichever-Novikov equation and its generalized version, no other local symmetries with low differential order are found to contain $t,x$. Third, the basic Hamiltonian structure of the Krichever-Novikov equation is used to map the local conserved density containing $t,x$ into a nonlocal symmetry that contains $t,x$. Fourth, a recursion operator is applied to this nonlocal symmetry to produce a hierarchy of nonlocal symmetries that have explicit dependence on $t,x$. When the inverse of the Hamiltonian map is applied to this hierarchy, only trivial conserved densities are obtained.

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Stephen C. Anco, Elena D. Avdonina, Aliya Gainetdinova, Laisan R. Galiakberova, Nail H. Ibragimov, Thomas Wolf. 2015-12-15. Symmetries and conservation laws of the generalized Krichever-Novikov equation. https://doi.org/10.1088/1751-8113%2F49%2F10%2F105201

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