数学物理学报(英文版) ›› 1994, Vol. 14 ›› Issue (4): 371-376.
蹇明
Jian Ming
摘要: Bernardi has proved that if f(z) is starlike univalent in the unit disk △, then so is the function g(z) given by
g(z)=(c+1)z-1∫0ztc-1f(t)dt,c=1,2….In this paper, we extend Bernardi's theorem to certain class Φp*(α,β,γ,ε,η;A) of p-valent starlike functions for operators. We prove that if f(A)∈Φp*(α,β,γ,ε,η;A), then g(A), defined by
g(A)=(p+c)∫01tc-1f(tA)dt,c=1,2,… also belongs to Φp*(α,β,γ,ε,η;A) and give a sufficient and necessary vondition with reference to f(A) ∈Φp*(α,β,γ,ε,η;A).