摘要
Nonlocal symmetries related to the B?cklund transformation(BT)for the modified KdV-sine-Gordon(mKdV-SG)equation are obtained by requiring the mKdV-SG equation and its BT form invariant under the infinitesimal transformations.Then through the parameter expansion procedure,an infinite number of new nonlocal symmetries and new nonlocal conservation laws related to the nonlocal symmetries are derived.Finally,several new finite and infinite dimensional nonlinear systems are presented by applying the nonlocal symmetries as symmetry constraint conditions on the BT.
基金
financial support by the National Natural Science Foundation of China(Grant Nos.11675055 and 12071302)
the Science and Technology Commission of Shanghai Municipality(Grant No.18dz2271000)。
