Pradyumna is Krishna's plenary expansion like Vasudeva, Aniruddha and Sankarsana. When Krishna appeared on the earth Pradyumna appeared as His son born of Rukmini. The immediate expansion of Krishna is Baladeva. who appeared as elder brother of Krishna and Baladeva. expands Himself further as Sankarsana, Vasudeva, Pradyumna, and Aniruddha. There are such innumerable expansions of Krishna and Pradyumna is one of them. There is no difference in potency of all these expansions.