Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
4621741 | Journal of Mathematical Analysis and Applications | 2008 | 13 Pages |
Abstract
In this paper, we consider the generalized Roper-Suffridge extension operator defined byΦn,β2,γ2,â¦,βn,γn(f)(z)=(f(z1),(f(z1)z1)β2(fâ²(z1))γ2z2,â¦,(f(z1)z1)βn(fâ²(z1))γnzn) for z=(z1,z2,â¦,zn)âΩp1,p2,â¦,pn, where 0⩽βj⩽1, 0⩽γj⩽1âβj, pj>1, and we choose the branch of the power functions such that (f(z1)z1)βj|z1=0=1 and (fâ²(z1))γj|z1=0=1, j=1,2,â¦,n,Ωp1,p2,â¦,pn={(z1,z2,â¦,zn)âCn:âj=1n|zj|pj<1}. We prove that the set Φn,β2,γ2,â¦,βn,γn(S(U)) can be embedded in Loewner chains and give the answer to the problem of Liu Taishun. We also obtain that the operator Φn,β2,γ2,â¦,βn,γn(f) preserves starlikeness or spirallikeness of type α on Ωp1,p2,â¦,pn for some suitable constants βj, γj, where S(U) is the class of all univalent analytic functions on the unit disc U in the complex plane C with f(0)=0 and fâ²(0)=1.
Keywords
Related Topics
Physical Sciences and Engineering
Mathematics
Analysis
Authors
Yu-Can Zhu, Ming-Sheng Liu,