What do you mean, lonely waves send the old?

Ding is thin and his children are not prosperous. Farewell to an old man is that he is thin, his children are not prosperous, and he has something on his mind. Literally, the meaning of "loneliness" is unique. Saying goodbye to old people alone means having a son by their side when they die. Soliton, also known as solitary wave, is a special type of ultrashort pulse, or a pulse-like traveling wave whose shape, amplitude and velocity remain unchanged during propagation.