Acta mathematica scientia, Series B >
A BOUNDARY SCHWARZ LEMMA FOR PLURIHARMONIC MAPPINGS FROM THE UNIT POLYDISK TO THE UNIT BALL
Received date: 2017-05-16
Online published: 2018-06-25
Supported by
Supported by the Natural and Science Foundation of China (61379001, 61771001).
In this article, we present a Schwarz lemma at the boundary for pluriharmonic mappings from the unit polydisk to the unit ball, which generalizes classical Schwarz lemma for bounded harmonic functions to higher dimensions. It is proved that if the pluriharmonic mapping f ∈ P(Dn, BN) is C1+α at z0 ∈ Er ⊂ ∂Dn with f(0)=0 and f(z0)=w0 ∈ ∂BN for any n, N ≥ 1, then there exist a nonnegative vector λf=(λ1,0, …, λr, 0, …,0)T ∈ R2n satisfying λi ≥ 1/22n-1 for 1 ≤ i ≤ r such that
(Df(z'0))T w'0=diag(λf)z'0,
where z'0 and w'0 are real versions of z0 and w0, respectively.
Key words: Boundary Schwarz lemma; pluriharmonic mapping; unit polydisk; unit ball
Ling LI , Hongyi LI , Di ZHAO . A BOUNDARY SCHWARZ LEMMA FOR PLURIHARMONIC MAPPINGS FROM THE UNIT POLYDISK TO THE UNIT BALL[J]. Acta mathematica scientia, Series B, 2018 , 38(3) : 926 -934 . DOI: 10.1016/S0252-9602(18)30793-8
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