Derivatives of meromorphic functions and exponential functions

摘要

We take up a new method to prove a Picard type theorem.Let f be a meromorphic function in the complex plane,whose zeros are multiple,and let R be a M(o)bius transformation.If ()limγ→∞T(γ,f)/γ2 =∞,then f'(z) =R(ez) has infinitely many solutions in the complex plane.