@article {
author = {Wu, J. and Wu, Z.},
title = {Characteristic function of a meromorphic function and its derivatives},
journal = {Bulletin of the Iranian Mathematical Society},
volume = {39},
number = {6},
pages = {1117-1123},
year = {2013},
publisher = {Iranian Mathematical Society (IMS)},
issn = {1017-060X},
eissn = {1735-8515},
doi = {},
abstract = {In this paper, some results of Singh, Gopalakrishna and Kulkarni (1970s) have been extended to higher order derivatives. It has been shown that, if $sumlimits_{a}Theta(a, f)=2$ holds for a meromorphic function $f(z)$ of finite order, then for any positive integer $k,$ $T(r, f)sim T(r, f^{(k)}), rrightarrowinfty$ if $Theta(infty, f)=1$ and $T(r, f)sim (k+1)T(r, f^{(k)}), rrightarrowinfty$ if $Theta(infty, f)=0.$},
keywords = {characteristic function,Nevanlinna's deficiency,maximum deficiency sum},
url = {http://bims.iranjournals.ir/article_464.html},
eprint = {http://bims.iranjournals.ir/article_464_28b526931ff60ee50847aaedcce35cc0.pdf}
}