Derivatives of meromorphic functions sharing two sets with least cardinalities

Abstract

Abstract In this paper, we prove two theorems establishing the uniqueness of the derivatives of meromorphic functions {f^{{(k)}\vphantom{k}}} and {g^{{(k)}\vphantom{k}}} when they share two sets with least cardinalities. Our results improve some existing results of Fang–Lahiri, Banerjee–Bhattacharjee, Banerjee–Mallick and Banerjee–Chakraborty.