Abstract
The following notion of bounded index for complex entire functions was presented by Lepson. function f(z) is of bounded index if there exists an integer N independent of z, such that
The main goal of this paper is extend this notion to holomorphic bivariate function. To that end, we obtain the following definition. A holomorphic bivariate function is of bounded index, if there exist two integers M and N such that M and N are the least integers such that
Using this notion we present necessary and sufficient conditions that ensure that a holomorphic bivariate function is of bounded index.
References
[1] Fricke, G. H.: A characterization of functions of bounded index, Indian J. Math. 14 (1972), 207–212.Search in Google Scholar
[2] Hamilton, H. J.: Transformations of multiple sequences, Duke Math. J. 2 (1936), 29–60.10.1215/S0012-7094-36-00204-1Search in Google Scholar
[3] Hardy, G. H.: Divergent Series, Oxford University Press, 1949.Search in Google Scholar
[4] Lepson, B.: Differential equations of infinite order, hyperdirichlet series and entire functions of bounded index. Lecture Notes, 1966, Summer Institute on Entire Functions, Univ. of California, La Jolla, California.Search in Google Scholar
[5] Patterson, R. F.: Analogues of some fundamental theorems of summability theory, Int. J. Math. Math. Sci. 23, (2000), 1-9.10.1155/S0161171200001782Search in Google Scholar
[6] Pringsheim, A.: Zür Theorie der zweifach unendlichen Zahlenfolgen, Math. Ann. 53 (1900), 289–321.10.1007/BF01448977Search in Google Scholar
[7] Robison, G. M.: Divergent double sequences and series, Amer. Math. Soc. Trans. 28 (1926), 50–73.10.1090/S0002-9947-1926-1501332-5Search in Google Scholar
© 2017 Mathematical Institute Slovak Academy of Sciences