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Junfeng Xu

Publications and source records attributed to Junfeng Xu.

13 recordsLinked to original sources
arXiv2026

On the structure and classification of solutions to certain nonlinear differential equations

This paper is devoted to the study of meromorphic solutions of nonlinear differential equations, specifically the equation \[ (f^n)^{(k)}(g^n)^{(k)} = \alpha^2, \] where $k$ and $n$ are positive integers with $n>2k$, and $\alpha$ is a common small function of $f$ and $g$. Our main results provide a detailed characterization of the solutions, improving upon earlier works by Fang-Qiu [5], Fang [4], Zhang-Xu [19], and Li-Yi [9]. Notably, we identify and correct significant errors in the proof of Lemma 2.11 [13], which represents the most recent contribution in this area and provide a resolved and rigorous treatment of the problem. Equations of this type arise naturally in various areas of mathematics and applied sciences such as in the study of complex dynamical systems, integrable systems and value distribution theory in complex analysis. Moreover, understanding the meromorphic solutions helps to realize the growth behavior of solutions, stability analysis and modeling of phenomena in physics and engineering. By characterizing these solutions, one can develop methods to solve broader classes of nonlinear differential equations and explore their qualitative properties, which are essential for both theoretical studies and practical applications.

math.CV↗
arXiv2025

Relationship between the value-sharing behavior of an entire function and its derivative, and the analytic structure of a nonlinear differential equation

In this paper, we study uniqueness problems for entire functions that partially share two values with their higher-order derivatives. The results obtained here both improve and generalize the related results of Li and Yi \cite{LYi}, L\"{u} et al. \cite{LXY1} and Sauer and Schweizer \cite{SS1}. Furthermore, we show that our results reveal a deep relationship between the value-sharing behavior of an entire function $f$ and its $k$-th derivative $f^{(k)}$, and the analytic structure of a particular type of nonlinear differential equation. Several examples are provided to illustrate the necessity of the conditions used in our results.

math.CV↗
arXiv2025

On the existence of entire solutions to a system of nonlinear Fermat-type partial differential-difference equations

The aim of this study is to investigate the precise form of finite-order entire solutions to the following system of Fermat-type partial differential-difference equations: \beas \begin{cases} \left(\frac{\partial f_1\left(z_1, z_2, \ldots, z_m \right)}{\partial z_1}\right)^{n_1} + f_2^{m_1} \left(z_1 + c_1, z_2 + c_2, \ldots, z_m + c_m \right) = 1,\\ \left(\frac{\partial f_2\left(z_1, z_2, \ldots, z_m \right)}{\partial z_1}\right)^{n_2} + f_1^{m_2} \left(z_1 + c_1, z_2 + c_2, \ldots, z_m + c_m \right) = 1 \end{cases} \eeas for various combinations of the positive integers $n_1$, $n_2$, $m_1$ and $m_2$. Our results extend the work of Xu et al. (Entire solutions for several systems of non-linear difference and partial differential-difference equations of Fermat-type, J. Math. Anal. Appl., 483(2), 2020), generalizing the setting $\mathbb{C}^2$ to $\mathbb{C}^m$. Several examples are provided to illustrate the applicability and sharpness of the obtained results.

math.CV↗
arXiv2025

Entire solution of a partial differential equation

In this paper, using Nevanlinna's value distribution theory of meromorphic functions in several complex variables, we study for the existence of entire solutions $f$ in $\mathbb{C}^2$ of the following partial differential equation \[a_1\left(\frac{\partial f(z_1,z_2)}{\partial z_1}\right)^n+a_2f^n(z_1,z_2)=p_1e^{r(z_1,z_2)}+p_2e^{s(z_1,z_2)},\] where $n$ is a positive integer such that $n\geq 3$, $a_1,a_2,p_1,p_2$ are non-zero constants and $r(z_1,z_2), s(z_1,z_2)$ are arbitrary polynomials in $\mathbb{C}^2$.

math.CV↗
arXiv2025

Meromorphic solution of a certain type of algebraic differential equation

In the paper, we use the idea of normal family to find out the possible solution of the following special case of algebraic differential equation \[P_k\big(z,f,f^{(1)},\ldots, f^{(k)}\big)=f^{(1)}(f-\mathscr{L}_k(f))-\varphi (f-a)(f-b)=0,\] where $\mathscr{L}_k(f)=\sideset{}{_{i=0}^k}{\sum} a_i f^{(i)}$ and $\varphi$ is an entire function, $a_i\in\mathbb{C}\;(i=0,1,\ldots, k)$ such that $a_k=1$ and $a, b\in\mathbb{C}$ such that $a\neq b$. The obtained results improve and generalise the results of Li and Yang \cite{LY1} and Xu et al. \cite{XMD} in a large scale.

math.CV↗
arXiv2025

Entire solutions of a certain type differential-difference equation and differential-difference analogue of Bruck conjecture

In the paper, we find out the precise form of the finite order entire solutions of the following differential-difference equation \[f^{(k)}(z)=\sideset{}{^n_{j=0}}{\sum} a_j f(z+jc),\] where $a_0, a_1,\ldots,a_n(\neq 0)\in\mathbb{C}$. Also in the paper we study the differential-difference analogue of Br\"{u}ck conjecture and derive a uniqueness result of finite order entire function $f(z)$ having a Borel exceptional small function of $f(z)$, when $f^{(k)}(z)$ and $\sideset{}{^n_{j=0}}{\sum} a_j f(z+jc)$ share a small function of $f(z)$. The obtained results, significantly generalize and improve the results due to Liu and Dong (Some results related to complex differential-difference equations of certain types, Bull. Korean Math. Soc., 51 (5) (2014), 1453-1467). Some examples are given to ensure the necessity of the condition (s) of our main results.

math.CV↗
arXiv2025

Estimation for the logarithmic partial derivative and Wiman-Valiron theory in several complex variables

The first objective of the paper is to estimate logarithmic partial derivative for meromorphic functions in several complex variables. Our estimations for logarithmic partial derivatives extend the results of Gundersen \cite{GG2} to the higher dimensions. The second objective of the paper is to study Wiman-Valiron theory into higher dimensions. The third objective of this paper is to study the growth of solutions of a class of complex partial differential equations and our obtained result is the extension of the result of Cao \cite{c2} from $\mathbb{C}$ to $\mathbb{C}^m$.

math.CV↗
arXiv2023

APT Encrypted Traffic Detection Method based on Two-Parties and Multi-Session for IoT

APT traffic detection is an important task in network security domain, which is of great significance in the field of enterprise security. Most APT traffic uses encrypted communication protocol as data transmission medium, which greatly increases the difficulty of detection. This paper analyzes the existing problems of current APT encrypted traffic detection methods based on machine learning, and proposes an APT encrypted traffic detection method based on two parties and multi-session. This method only needs to extract a small amount of features, such as session sequence, session time interval, upstream and downstream data size, and convert them into images. Then convolutional neural network method can be used to realize image recognition. Thus, network traffic identification can be realized too. In the preliminary test of five experiments, this method achieves good experimental results, which verifies the effectiveness of the method.

cs.CR↗
arXiv2020

Sampling expansions associated with quaternion difference equations

Starting with a quaternion difference equation with boundary conditions, a parameterized sequence which is complete in finite dimensional quaternion Hilbert space is derived. By employing the parameterized sequence as the kernel of discrete transform, we form a quaternion function space whose elements have sampling expansions. Moreover, through formulating boundary-value problems, we make a connection between a class of tridiagonal quaternion matrices and polynomials with quaternion coefficients. We show that for a tridiagonal symmetric quaternion matrix, one can always associate a quaternion characteristic polynomial whose roots are eigenvalues of the matrix. Several examples are given to illustrate the results.

math.CA↗
arXiv2020

The exact entire solutions of certain type of nonlinear difference equations

In this paper, we consider the entire solutions of nonlinear difference equation $$f^3+q(z)Δf=p_1 e^{α_1 z}+ p_2 e^{α_2 z} $$ where $q$ is a polynomial, and $p_1, p_2, α_1, α_2$ are nonzero constants with $α_1\neq α_2$. It is showed that if $f$ is a non-constant entire solution of $ρ_2(f)<1$ to the above equation, then $f(z)=e_1e^{\frac{α_1 z}{3}}+e_2e^{\frac{α_2 z}{3}}, $ where $e_1$ and $e_2$ are two constants. Meanwhile, we give an affirmative answer to the conjecture posed by Zhang et al in [18].

math.CV↗
arXiv2014

Some Inequalities of differential polynomials II

In this paper, we consider the value distribution of the differential polynomials $f^2f^{(k)}-1$ where $k$ is a positive integer, and obtain some estimates only by the reduced counting function. Our result answers a question in (Some inequalities of differential polynomials, Mathematical Inequalities and Applications, \textbf{12}(2009), no.1, 99--113) completely.

math.CV↗
arXiv2014

A note on a famous theorem of Pang and Zalcman

In this paper, by studying the famous theorem of Pang and Zalcman, we find a normal family and obtain a result, which is an improvement of Pang and Zalcman's theorem in some sense. Meanwhile, several examples are provided to show that our result's conditions are necessary.

math.CV↗