Jen-Hsu CHANG
Department of General Courses,
Chung- Cheng Institute of Technology,
National Defense University,
Dashi, Tau-Yuan County,
33509 TAIWAN
E-mail: jhchang@ccit.edu.tw

Approximately rational symmetries of KdV equation

Abstract:
We construct one-parameter deformation of  the Dorfman Hamiltonian operator for the Riemann hierarchy using the quasi-Miura transformation from topological field theory. In this way, one can get the approximately rational symmetries of KdV equation and then investigate its bi-Hamiltonian structure.