Schlicht regions for entire and meromorphic functions
Author(s) -
Mario Bonk,
Alexandre Erëmenko
Publication year - 1999
Publication title -
journal d analyse mathématique
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.189
H-Index - 53
eISSN - 1565-8538
pISSN - 0021-7670
DOI - 10.1007/bf02791258
Subject(s) - meromorphic function , mathematics , genus , normality , metric (unit) , class (philosophy) , elliptic function , rational function , pure mathematics , infinity , function (biology) , algebraic number , degree (music) , mathematical analysis , computer science , statistics , economics , biology , operations management , artificial intelligence , evolutionary biology , botany , physics , acoustics
Let f:C →C be a meromorpMc function. We study the size of the maximal disc inC, with respect to the spherical metric, in which a single-valued branch of f-1 exists. This problem is related to normality and type criteria. Best possible lower estimates of the size of such discs are obtained for entire functions and a class of meromorphic functions containing all elliptic functions. An estimate for the class of rational functions is also given which is best possible for rational functions of degree 7. For algebraic functions of given genus we obtain an estimate which is precise for genera 2 and 5 and asymptotically best possible when the genus tends to infinity.
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