Most Down Articles

    Published in last 1 year | In last 2 years| In last 3 years| All| Most Downloaded in Recent Month | Most Downloaded in Recent Year|

    In last 2 years
    Please wait a minute...
    Parameter Estimation for an Ornstein-Uhlenbeck Process Driven by a Type of Gaussian Noise with Hurst Parameter $H\in (0,\frac{1}{2})$
    Chen Yong,Li Ying,Sheng Ying,Gu Xiangmeng
    Acta mathematica scientia,Series A    2023, 43 (5): 1483-1518.  
    Abstract137)   HTML6)    PDF(pc) (867KB)(638)       Save

    In 2021, Chen and Zhou consider an inference problem for an Ornstein-Uhlenbeck process driven by a type of centered fractional Gaussian process $(G_t)_{t\ge 0}$. The second order mixed partial derivative of the covariance function $ R(t,\, s)=\mathbb{E}[G_t G_s]$ can be decomposed into two parts, one of which coincides with that of fractional Brownian motion and the other is bounded by $(ts)^{H-1}$ with $H\in (\frac12,\,1)$, up to a constant factor. In this paper, we investigate the same problem but with the assumption of $H\in (0,\,\frac12)$. It is well known that there is a significant difference between the Hilbert space associated with the fractional Gaussian processes in the case of $H\in (\frac12, 1)$ and that of $H\in (0, \frac12)$. The starting point of this paper is a quantitative relation between the inner product of $\mathfrak{H}$ associated with the Gaussian process $(G_t)_{t\ge 0}$ and that of the Hilbert space $\mathfrak{H}_1$ associated with the fractional Brownian motion $(B^{H}_t)_{t\ge 0}$. We prove the strong consistency with $H\in (0, \frac12)$, and the asymptotic normality and the Berry-Esséen bounds with $H\in (0,\frac38)$ for both the least squares estimator and the moment estimator of the drift parameter based on the continuous observations.

    Reference | Related Articles | Metrics
    Some Properties of Quasi-Periodic Functions and Their Applications
    Hu Keqi, Zhang Qingcai
    Acta mathematica scientia,Series A    2024, 44 (6): 1415-1425.  
    Abstract285)   HTML10)    PDF(pc) (560KB)(532)       Save

    In this paper, we estimate relevant properties of quasi-periodic functions, and these properties are applied. Under the additional condition, the conjecture proposed by Yang is solved.

    Reference | Related Articles | Metrics
    The Schödinger Uncertainty Relation in the Fock-Type Spaces
    Li Wenxin,Lian Pan,Liang Yuxia
    Acta mathematica scientia,Series A    2023, 43 (5): 1321-1332.  
    Abstract290)   HTML21)    PDF(pc) (660KB)(530)       Save

    In this paper, the Schödinger uncertainty relation for the unilateral weighted shift operators on Fock space is established, and the explicit expression when the equality attained is given, which further extends the Heisenberg uncertainty relation on Fock space established in [4] and overcomes the difficulty in [16]. In addition, we generalize the uncertainty relation to the multiple operators case. A new uncertainty inequality in the form of non-self adjoint operators is obtained as well.

    Reference | Related Articles | Metrics
    Normalized Solutions of the Quasilinear Schrödinger System in Bounded Domains
    Zhang Qian
    Acta mathematica scientia,Series A    2025, 45 (1): 1-30.  
    Abstract337)   HTML12)    PDF(pc) (779KB)(463)       Save

    This paper is concerned with the following nonlinear coupled system
    $\left\{\begin{array}{l} -\Delta u_{1}+\omega_{1} u_{1}-\frac{1}{2} \Delta\left(u_{1}^{2}\right) u_{1}=\mu_{1}\left|u_{1}\right|^{p-1} u_{1}+\beta\left|u_{2}\right|^{\frac{p+1}{2}}\left|u_{1}\right|^{\frac{p-3}{2}} u_{1} \\ -\Delta u_{2}+\omega_{2} u_{2}-\frac{1}{2} \Delta\left(u_{2}^{2}\right) u_{2}=\mu_{2}\left|u_{2}\right|^{p-1} u_{2}+\beta\left|u_{1}\right|^{\frac{p+1}{2}}\left|u_{2}\right|^{\frac{p-3}{2}} u_{2} \\ \int_{\Omega}\left|u_{i}\right|^{2} \mathrm{~d} x=\rho_{i}, \quad i=1,2, \quad\left(u_{1}, u_{2}\right) \in H_{0}^{1}\left(\Omega ; \mathbb{R}^{2}\right) \end{array}\right.$
    and linear coupled system
    $\left\{\begin{array}{l} -\Delta u_{1}+\omega_{1} u_{1}-\frac{1}{2} \Delta\left(u_{1}^{2}\right) u_{1}=\mu_{1}\left|u_{1}\right|^{p-1} u_{1}+\beta u_{2} \\ -\Delta u_{2}+\omega_{2} u_{2}-\frac{1}{2} \Delta\left(u_{2}^{2}\right) u_{2}=\mu_{2}\left|u_{2}\right|^{p-1} u_{2}+\beta u_{1} \\ \int_{\Omega}\left|u_{i}\right|^{2} \mathrm{~d} x=\rho_{i}, \quad i=1,2, \quad\left(u_{1}, u_{2}\right) \in H_{0}^{1}\left(\Omega ; \mathbb{R}^{2}\right) \end{array}\right.$
    where $\Omega\subset\mathbb R^N(N\geq1)$ is a bounded smooth domain, $\omega_i,\ \beta\in\mathbb R$, $\mu_i,\ \rho_i>0,\ i=1,2.$ Moreover, $p>1$ if $N=1,2$ and $1<p\leqslant\frac{3N+2}{N-2}$ if $N\geqslant3$. Using change of variables, on the one hand, we prove the existence and stability of normalized solutions in nonlinear coupled system and the limiting behavior of normalized solutions as $\beta\rightarrow -\infty$. On the other hand, we apply the minimization constraint technique to obtain the existence of normalized solutions for linear coupled system. Compared with some previous results, we extend the existing results to the quasilinear Schrödinger system and also obtain normalized solutions for the linear coupling case.

    Reference | Related Articles | Metrics
    An Extension of Minkowski Formulae for Free Boundary Hypersurfaces in a Ball
    Sheng Weimin, Wang Yinhang
    Acta mathematica scientia,Series A    2023, 43 (6): 1641-1648.  
    Abstract277)   HTML21)    PDF(pc) (508KB)(455)       Save

    In this article, we prove a generalization of Hsiung-Minkowski formula for free boundary hypersurfaces in a ball in space forms. As corollaries, we obtain some Alexandrov-type results.

    Table and Figures | Reference | Related Articles | Metrics
    On the Blow-Up Solutions of Inhomogeneous Nonlinear Schrödinger Equation with a Partial Confinement
    Jian Hui, Gong Min, Wang Li
    Acta mathematica scientia,Series A    2023, 43 (5): 1350-1372.  
    Abstract153)   HTML5)    PDF(pc) (797KB)(428)       Save

    This paper is devoted to the Cauchy problem of inhomogeneous nonlinear Schrödinger equation in the presence of a partial confinement, which is an important model in Bose-Einstein condensates. Combining the variational characterization of the ground state of a nonlinear elliptic equation and the conservations of mass and energy, we first obtain a global solution and show the existence of blow-up solutions for some special initial data by scaling techniques. Then, we study the $L^2$-concentration phenomenon for the blow-up solutions. Finally, we apply the variational arguments connected to the above ground state to investigate the dynamics of $L^2$-minimal blow-up solutions, i.e., the limiting profile, mass-concentration and blow-up rate of the blow-up solutions with minimal mass. We extend the global existence and blow-up results of Zhang[34] to the case of inhomogeneous nonlinearities and improve partial results of Pan and Zhang[23] to space dimensions $N\geq2$ in the inhomogeneous case.

    Reference | Related Articles | Metrics
    Time Decay Rate for Large-Solution About 3D Compressible MHD Equations
    Chen Fei,Wang Shuai,Zhao Yongye,Wang Chuanbao
    Acta mathematica scientia,Series A    2023, 43 (5): 1397-1408.  
    Abstract143)   HTML4)    PDF(pc) (697KB)(424)       Save

    This paper focus on time decay rate for large-solution about compressible magnetohydrodynamic equations in $\mathbb{R}^3$. Provided that $(\sigma_{0}-1,u_{0},M_{0})\in L^1\cap H^2$, based on the work of Chen et al.[1], $\|\nabla(\sigma-1,u,M)\|_{H^1}\leqslant C(1+t)^{-\frac{5}{4}}$ is obtained in reference [2], obviously, time decay rate of the 2nd-order derivative of the solution in [2] is not ideal. Here, we improve that of $\|\nabla^2 (\sigma-1,u,M)\|_{L^2}$ to be $(1+t)^{-\frac{7}{4}}$ by the frequency decomposition method[3].

    Reference | Related Articles | Metrics
    The Complete Classification of Solutions to the Step Initial Condition: Analysis and Numerical Verification for the Generalized Gardner Equation in Fluid Mechanics
    Zhang Yan, Hao Huiqin, Guo Rui
    Acta mathematica scientia,Series A    2024, 44 (5): 1242-1282.  
    Abstract75)   HTML3)    PDF(pc) (10179KB)(394)       Save

    In this paper, we investigate the evolution of the initial discontinuity for the generalized Gardner equation through the Whitham modulation theory, which the generalized Gardner equation can describe the transcritical flow of stratified fluids over topography. Firstly, we derive the linear harmonic wave, soliton and nonlinear trigonometric wave in different limiting cases via the periodic waves represented by the Jacobi elliptic functions. Then we obtain the Whitham characteristic velocities and modulation system based on the Riemann invariants by the finite-gap integration method. Since the modulation system of the generalized Gardner equation is neither strictly elliptic nor hyperbolic type, which makes the dynamical evolution behavior more varied in different regions compared to the KdV equation. Furthermore, we perform a complete classification for all wave structures in the cases of positive and negative cubic nonlinear terms, including the dispersive shock wave, rarefaction wave, trigonometric dispersive shock wave, solibore and their combinations. In addition, the correctness of the results is verified by numerical simulations, and the numerical solutions are in good agreement with the analytical solutions. Finally, the influences of the coefficients of the linear and nonlinear terms on the step initial value problem under certain conditions are analyzed.

    Table and Figures | Reference | Related Articles | Metrics
    The Inner Layer of a Class of Singularly Perturbed High-Order Equations with Discontinuous Right-Hand Side
    Fu Yuechen, Ni Mingkang
    Acta mathematica scientia,Series A    2024, 44 (5): 1153-1166.  
    Abstract97)   HTML2)    PDF(pc) (711KB)(391)       Save

    This paper introduces some work on singular perturbation problems with discontinuous right-hand side, mainly discusses a class of fourth-order Dirichlet boundary value singular perturbation equations with discontinuous right-hand sides. After introducing complex equation form, we construct a formal asymptotic solution with an internal transfer layer by using the boundary layer function method, and give the existence and residual estimation of smooth solutions. Finally, an example is given to verify the correctness of the algorithm.

    Table and Figures | Reference | Related Articles | Metrics
    Exact Multiplicity of Positive Solutions for a Semipositone Mean Curvature Problem with Concave Nonlinearity
    Li Xiaodong, Gao Hongliang, Xu Jing
    Acta mathematica scientia,Series A    2023, 43 (5): 1341-1349.  
    Abstract104)   HTML8)    PDF(pc) (770KB)(386)       Save

    In this paper, we study the exact multiplicity and bifurcation diagrams of positive solutions for the prescribed mean curvature problem in one-dimensional Minkowski space in the form of

    $ \left\{\begin{array}{ll} -\left(\frac{u'}{\sqrt{1-u'^{2}}}\right)'=\lambda f(u), x\in(-L,L),\\ u(-L)=0=u(L), \end{array} \right. $

    where $\lambda>0$ is a bifurcation parameter and $L>0$ is an evolution parameters, $f\in C^{2}([0,\infty), \mathbb{R})$ satisfies $f(0)<0$ and $f$ is concave for $0. In two different cases, we obtain that the above problem has zero, exactly one, or exactly two positive solutions according to different ranges of $\lambda$. The arguments are based upon a detailed analysis of the time map.

    Table and Figures | Reference | Related Articles | Metrics
    Existence of Positive Solutions for a Class of Schrödinger-Newton Systems with Critical Exponent
    Cheng Qingfang,Liao Jiafeng,Yuan Yanxiang
    Acta mathematica scientia,Series A    2023, 43 (5): 1373-1381.  
    Abstract142)   HTML6)    PDF(pc) (629KB)(379)       Save

    In this paper, we study the existence of positive solutions for a class of Schrödinger-Newton system with critical exponents on bounded domain, and obtain two positive solutions by the variational method.

    Reference | Related Articles | Metrics
    The Radial Symmetry and Monotonicity of Entire Solutions for Fractional Parabolic Equations
    Tang Yanjuan
    Acta mathematica scientia,Series A    2023, 43 (5): 1409-1416.  
    Abstract131)   HTML3)    PDF(pc) (581KB)(377)       Save

    This paper mainly develops the radial symmetry and monotonicity of entire solutions for fractional parabolic equations. To obtain the symmetry and monotonicity of entire solutions, the narrow region principle and maximum principle for antisymmetric functions in [9] are needed. Furthermore, to circumvent the difficulty from nonlocality for the fractional Laplacian, a fractional parabolic version of the method of moving planes will be adopted.

    Reference | Related Articles | Metrics
    Two-Step Inertial Bregman Proximal Alternating Linearized Minimization Algorithm for Nonconvex and Nonsmooth Problems
    Jing Zhao, Chenzheng Guo
    Acta mathematica scientia,Series A    2024, 44 (6): 1630-1651.  
    Abstract153)   HTML1)    PDF(pc) (9184KB)(376)       Save

    In this paper, for solving a class of nonconvex and nonsmooth nonseparable optimization problems, based on proximal alternating linearized minimization method we propose a new iterative algorithm which combines two-step inertial extrapolation and Bregman distance. By constructing appropriate benefit function, with the help of Kurdyka-Łojasiewicz property we establish the convergence of the whole sequence generated by proposed algorithm. We apply the proposed algorithm to solve sparse nonnegative matrix factorization, signal recovery and quadratic fractional programming problems, and show the effectiveness of proposed algorithm.

    Table and Figures | Reference | Related Articles | Metrics
    Survival Analysis of an SVIR Epidemic Model with Media Coverage
    Li Dan,Wei Fengying,Mao Xuerong
    Acta mathematica scientia,Series A    2023, 43 (5): 1595-1606.  
    Abstract161)   HTML4)    PDF(pc) (1602KB)(373)       Save

    We consider the long-term properties of a stochastic SVIR epidemic model with media coverage and the logistic growth in this paper. We firstly derive the fitness of a unique global positive solution. Then we construct appropriate Lyapunov functions and obtain the existence of ergodic stationary distribution when ${R}_{0}^{s}>1$ is valid, and also derive sufficient conditions for persistence in the mean. Moreover, the exponential extinction to the density of the infected is figured out when ${R}_{0}^{e}<1$ holds.

    Table and Figures | Reference | Related Articles | Metrics
    Degeneration Behaviors of Solutions and Hybrid Solutions for the New (3+1)-Dimensional KP Equation
    Guo Yanfeng, Cui Jingyi, Xiao Haijun, Zhang Jingjun
    Acta mathematica scientia,Series A    2024, 44 (6): 1520-1536.  
    Abstract78)   HTML1)    PDF(pc) (6402KB)(370)       Save

    We concentrate on the nonlinear wave solutions of the new (3+1)-dimensional KP equation, which was firstly proposed by Wazwaz in 2022. Based on the Hirota bilinear form, the $ P $-breathing solutions are mainly obtained from the $ N $-soliton solutions utilizing the module resonance technique. Then, using parameter limit approach, the Lump solutions are derived by degenerating behaviors of the homoclinic breathing solutions and $ N $-soliton solutions on the basis of the special relations of parameters. In addition, from the partial degeneration of the $ N $-soliton solutions, some hybrid solutions are investigated by the interaction solutions among the breathing, soliton and Lump solutions.

    Table and Figures | Reference | Related Articles | Metrics
    Global Bifurcation for the Yamabe Equation on the Unit Sphere
    Dai Guowei,Gao Siyu,Ma Ruyun
    Acta mathematica scientia,Series A    2023, 43 (5): 1391-1396.  
    Abstract131)   HTML3)    PDF(pc) (629KB)(365)       Save

    We study the Yamabe equation on the $N$-dimensional unit sphere $\mathbb{S}^N$

    $\begin{equation} -\Delta_{\mathbb{S}^N} v+\lambda v=v^{\frac{N+2}{N-2}}.\nonumber \end{equation}$

    By bifurcation technique, for each $k\geq1$, we prove that this equation has at least one non-constant solution $v_k$ for any $\lambda>\lambda_k:=(k+N-1)(N-2)/4$ such that $v_k-\lambda^{1/(N^{*}-1)}$ has exactly $k$ zeroes, all of them are in $(-1, 1)$ and are simple, where $N^{*}$ is the sobolev critical exponent. As application, we obtain the existence of non-radial solutions of a nonlinear elliptic equation on $\mathbb{R}^N$ with $n\geq4$. Moreover, we also obtain the global bifurcation results of the Yamabe problem in product manifolds with one of the manifold is the unit sphere.

    Reference | Related Articles | Metrics
    Properties and Computations of the $\mathfrak{m}$-WG Inverse
    Wei Huaquan, Wu Hui, Liu Xiaoji, Jin Hongwei
    Acta mathematica scientia,Series A    2024, 44 (3): 547-562.  
    Abstract239)   HTML2)    PDF(pc) (736KB)(363)       Save

    In this paper, the properties and computations of the $\mathfrak{m}$-WG inverse in Minskowski space are presented. Firstly, the characterization of the $\mathfrak{m}$-WG inverse is given by using the range and null space. Secondly, the relationship between the $\mathfrak{m}$-WG inverse and an invertible bordered matrix is given. Moreover, the perturbation bounds of the $\mathfrak{m}$-WG inverse is discussed. Finally, the successive matrix squaring algorithm is used to compute the $\mathfrak{m}$-WG inverse.

    Reference | Related Articles | Metrics
    Blow-Up Conditions of Porous Medium Systems with Gradient Source Terms and Nonlinear Boundary Conditions
    Shen Xuhui,Ding Juntang
    Acta mathematica scientia,Series A    2023, 43 (5): 1417-1426.  
    Abstract88)   HTML5)    PDF(pc) (602KB)(362)       Save

    In this paper, we consider the blow-up of solutions to the following porous medium systems:

    $ \left\{ \begin{array}{ll} u_{t} =\Delta u^l+f(u,v,|\nabla u|^2,t), & \\\displaystyle v_{t} =\Delta v^m+g(u,v,|\nabla v|^2,t),&x\in\Omega, \ t\in(0,t^*), \\\displaystyle \frac{\partial u}{\partial\nu}=p(u), \ \frac{\partial v}{\partial\nu}=q(v), &x\in\partial\Omega, \ t\in(0,t^*), \\\displaystyle u(x,0)=u_{0}(x), \ v(x,0)=v_{0}(x), &x\in\overline{\Omega}, \end{array} \right. $

    where $l,m>1, \ \Omega\subset\mathbb{R}^N \ (N\geq2)$ is a bounded domain with smooth boundary $\partial\Omega$. Using the differential inequality techniques and the maximum principles, we give a sufficient condition to ensure that the positive solution $(u,v)$ of the above problem is a blow-up solution that blows up at a certain finite time $t^*$. An upper estimate of $t^*$ and an upper estimate of the blow-up rate of $(u,v)$ are also obtained.

    Reference | Related Articles | Metrics
    Robust Accessible Hyperbolic Repelling Sets
    Xiao Jianrong
    Acta mathematica scientia,Series A    2024, 44 (1): 1-11.  
    Abstract246)   HTML13)    PDF(pc) (800KB)(360)       Save

    By operating Denjoy like surgery on a piecewise linear map, we constructed a family of$C^1$maps$f_\alpha \ (1<\alpha<3 )$admitting the following properties:

    1)$f_\alpha$admits a hyperbolic repelling Cantor set$\mathcal{A}_\alpha$with positive Lebesgue measure, and$\mathcal{A}_\alpha$is also a wild attractor of$f_{\alpha}$;

    2) The attractor$\mathcal{A}_\alpha$is accessible: the difference set$\mathbb{B}(A_\alpha)\backslash A_\alpha$between the basin of attraction$\mathbb{B}(A_\alpha)$and$A_\alpha$has positive Lebesgue measure;

    3) The family is structurally stable:$f_{\alpha}$is topologically conjugate to$f_{\alpha'}$for all$1<\alpha,\ \alpha'<3$.

    The surgery involves blowing up the discontinuity and its preimages set into open intervals. The$C^1$smoothness of$f_{\alpha}$is ensured by the prescribed lengths of glued intervals and the maps defined on the glued intervals.

    Table and Figures | Reference | Related Articles | Metrics
    Global Existence and Blow-Up for Semilinear Third Order Evolution Equation with Different Power Nonlinearities
    Shi Jincheng, Liu Yan
    Acta mathematica scientia,Series A    2024, 44 (6): 1550-1562.  
    Abstract88)   HTML0)    PDF(pc) (4733KB)(357)       Save

    This paper studies the Cauchy problem of a class of semilinear third-order evolution equations with different power-type nonlinear terms. Its linearized model is derived from the classical thermoelastic plate equations considering Fourier's law. Firstly, by using the appropriate $L^r\!-\!L^q$ estimation away from the asymptote and combining with the Banach fixed point theorem, the existence of the global solution under small initial conditions is obtained. Secondly, for the nonlinear terms that satisfy specific conditions, the explosion of the solution is proved by the test function method. Finally, based on these research results, some critical indicators of the semilinear third-order model are obtained.

    Reference | Related Articles | Metrics