Unicity of meromorphic functions and their derivatives

In this paper, we prove that if a transcendental meromorphic function f shares two distinct small functions CM with its kth derivative f (k) (k > 1), then f = f (k). We also resolve the same question for the case k = 1. These results generalize a result due to Frank and Weissenborn.  2003 Elsevier Inc. All rights reserved.