Comments on “New exact periodic solitary-wave solution of MKdV equation”

By means of a so-called extended homoclinic test method, Guo et al. (2009) [1] obtained exact periodic solitary-wave solutions of the modified Korteweg-de Vries (MKdV) equation. We point out that the bilinear form of MKdV equation given in above paper is not true, so that the obtained solutions in the above paper are not actual solutions of the equation. In this paper, we apply an extended ansatz to obtain some new exact periodic solitary-wave solutions to MKdV equation.