A pull-back measure formula obtained in some particular cases by E. A. Nordgren and this author is generalized in the framework of boundary measures for zero-free Nevanlinna class functions on the unit polydisk. The formula is used to characterize the zero-free Nevanlinna class functions which are solutions of Schröder's equation induced by a polydisk automorphism φ (i.e. to determine the zero-free functions f belonging to the Nevanlinna class which are solutions of the functional equation f o φ = λf, for some constant λ), thus generalizing earlier results obtained by R. Mortini and this author.
|Original language||English (US)|
|Number of pages||6|
|Journal||Integral Equations and Operator Theory|
|State||Published - Mar 2001|
ASJC Scopus subject areas
- Algebra and Number Theory