TY - JOUR
ID - 464
TI - Characteristic function of a meromorphic function and its derivatives
JO - Bulletin of the Iranian Mathematical Society
JA - BIMS
LA - en
SN - 1017-060X
AU - Wu, J.
AU - Wu, Z.
AD - Xianning Vocational and Technical College,
P.O. Box 437100, Xianning, P. R. China
AD - School of Mathematics and Statistics, Hubei University of Science and Technology,
P.O. Box 437100, Xianning, P. R. China
Y1 - 2013
PY - 2013
VL - 39
IS - 6
SP - 1117
EP - 1123
KW - characteristic function
KW - Nevanlinna's deficiency
KW - maximum deficiency sum
DO -
N2 - 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 $Theta(infty, f)=0.$
UR - http://bims.iranjournals.ir/article_464.html
L1 - http://bims.iranjournals.ir/article_464_28b526931ff60ee50847aaedcce35cc0.pdf
ER -