Normal Families of Meromorphic Functions Concerning Multiplicity of Zeros

A normality criterion of meromorphic functions is proved:let F be a family of functions meromorphic in a domain D,n,m,k be three positive integers such that n≥m+1 and a≠0,and b be two finite complex numbers.If for each f∈F,all zeros of f have multiplicity at least k+1,and fm+a(f(k))n≠ b in D,F is normal in D.