Suppose f is an almost starlike function of order α on the unit disk D. In this paper, we will prove that Фn,β2,γ2,…βn,γn(f)(z)=(f(z1),(f(z1)/z1)^β2(f'(z1))^γ2 z2,…,(f(z1)/z1)^βn(f'(z1))^γnzn)1 preserves almost starlikeness of order α on Ωn,p2,…,pn={z=(z1,z2,…,zn)'∈Cn:∑^n j=1|zj|^pj〈1},where 0〈p1≤2,pj≥1,j=2,…,n,are real numbers.
In this article, a normalized biholomorphic mapping f defined on bounded starlike circular domain in Cn is considered, where z = 0 is a zero of order k + 1 of f(z) - z. The sharp growth, covering theorems for almost starlike mappings of order α and starlike mappings of order α are established. Meanwhile, the construction of the above mappings on bounded starlike circular domain in Cn is also discussed, it provides the extremal mappings for the growth, covering theorems of the above mappings.
Suppose f is a spirallike function of type β and order α on the unit disk D.Let Ωn,p1,p2,…,pn={z=(z2,z2,…,zn)′∈C^n:∑j=1^n|zj)^Pj〈1},where 1≤p1≤2,pj≥1,j=2,…,n,are real numbers.In this paper,we will prove that Φn,β2,γ2,…βn,γn(f)(z)=(f(z1), preserves spirallikeness of type β and order α on Ωn,p1,p2,…,Pn.
In this article, first, a sufficient condition for a starlike mapping of order a f(x) defined on the unit ball in a complex Banach space is given. Second, the sharp estimate of the third homogeneous expansion for f is established as well, where f(z) = (f1(z), f2(z),..., fn(z))' is a starlike mapping of order a or a normalized biholomorphic starlike mapping defined on the unit polydisk in Cn, and D2fk(0)(z2) /2i= zk(∑l=1^b akzzl), k = 2t l=1 k = 1, 2,..., n. Our result states that the Bieberbaeh conjecture in several complex variables (the case of the third homogeneous expansion for starlike mappings of order α and biholomorphic starlike mappings) is partly proved.