摘要: Let F be a family of zero-free meromorphic functions in a domain D, let h(z)≡0 be a holomorphic function in D and let k be a positive integer.If,for each f∈F, P(f)(z)-h(z) has at most k distinct zeros(ignoring multiplicity)in D, where P(f)=f(k)(z)+a1(z)f(k-1)(z)+···+ak(z)f(z) is a diferential polynomial of f and aj(z)(j=1,2,···,k) are holomorphic functions in D, then F is normal in D. This extends the results due to Deng[2], Chang[1], Gu[3], Yang[12], etc.
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