Existence of Solutions to Systems of General Quadratic Functional Equations in $\mathbb{C}^n$
Molla Basir Ahamed, Sanju Mandal
TL;DR
The paper studies the existence and form of finite-order transcendental solutions to systems of general quadratic functional equations in ${\mathbb C}^n$ using Nevanlinna theory in several complex variables and its difference analogues. It analyzes three equation types—difference, partial differential, and partial differential-difference—under a nondegeneracy condition ${\Delta} \neq 0$ and derives explicit cosine–sine solution forms when possible, while proving nonexistence for a pure PDE system and providing explicit solutions for the difference and PDE–difference systems with precise parameter constraints. Corollaries extend the results to arbitrary coefficients and higher dimensions ($n\ge 2$), and illustrative examples confirm the existence of transcendental finite-order solutions. Overall, the work advances the understanding of how general quadratic structures constrain meromorphic solutions in several complex variables and broadens the scope beyond earlier work on fermat-type and trinomial equations.
Abstract
The main objective of this study is to investigate the existence and forms of solutions of systems of general quadratic functional equations in $\mathbb{C}^n$. By utilizing Nevanlinna theory in $\mathbb{C}^n$, we explore the existence and form of solutions for the several systems of general quadratic difference and partial differential-difference equations of the form $af^2 + 2αfg + bg^2 + 2βf + 2γg + C=0$, where $f$ and $g$ are non-constant meromorphic functions in $\mathbb{C}^n$. The obtained results in this article are improvements and generalizations of several results from [\textit{RACSAM}, \textbf{116}(8) (2022)]. Furthermore, appropriate remarks and illustrative examples are provided to validate and demonstrate the applicability of the obtained results concerning the existence and forms of solutions for such systems of equations.
