Abstract:
We study nonlocal symmetries of the Degasperis–Procesi equation, which are shown to be closely related to its integrable structure. First, applying the Hamiltonian operator to the gradients of the spectral parameter, we construct nonlocal symmetries of the Kaup–Kupershmidt equation. Next, we show that the nonlocal symmetries can be prolonged to local symmetries for a prolonged system by introducing new dependent variables. Finally, applying the Liouville transformation relating the Degasperis–Procesi and Kaup–Kupershmidt hierarchies, we obtain the corresponding nonlocal symmetries of the Degasperis–Procesi equation.
The work of Xiaoyong Li was supported by the National Natural
Science Foundation of China under grant No. 12431008 and K. C. Wong
Magna Fund in Ningbo University. The work of Changzheng Qu was
supported by the National Natural Science Foundation of China (grant
No. 12431008).