Normality through partial sharing of sets with differential polynomials
Kuldeep Singh Charak, Nikhil Bharti, Anil Singh
TL;DR
The paper develops normality criteria for families of meromorphic functions by using partial sharing of sets with differential polynomials, extending prior results that linked normality to sharing with derivatives. It introduces a differential-polynomial framework $P[f]=\sum_{i=1}^{m}a_i M_i[f]$, with normalized monomials $M_i$ and a key multiplicity parameter $\alpha$, and proves that if $f-a$ has zeros of multiplicity at least $\alpha+1$ for all $a\in S_1$ and $P[f](z)\in S_1$ implies $f(z)\in S_2$, then the family is normal in $D$; analogous criteria are established for normal meromorphic functions. The results generalize several known theorems (e.g., in the derivative setting) and answer questions about replacing derivatives with differential polynomials and about partial sharing, using a toolkit that combines Zalcman–Pang rescaling with Nevanlinna theory. Collectively, these findings broaden the scope of normality criteria in complex analysis and supply a unified approach to partial sharing with differential polynomials.
Abstract
This article aims at finding sufficient conditions for a family of meromorphic functions to be normal by involving partial sharing of sets with differential polynomials. Moreover, corresponding results for normal meromorphic functions are also established which improve and generalize many known results.
