Construction of higher-order smooth positons and breather positons via Hirota’s bilinear method

Based on the Hirota’s bilinear method, a more classic limit technique is perfected to obtain second-order smooth positons. Immediately afterwards, we propose an extremely ingenious approach in which higher-order positons and breather can be quickly derived from N-soliton solution. Under this technique, of modified Korteweg–de Vries system are easily derived. Compared with generalized Darboux transformation, mentioned paper has following advantages disadvantages: advantage that it simple fast disadvantage method cannot get concise general mathematical expression nth-order