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    Blow-Up of the Smooth Solutions to the Quantum Navier-Stokes-Landau-Lifshitz Equations
    Zhen Qiu,Guangwu Wang
    Acta mathematica scientia,Series A    2022, 42 (4): 1074-1088.  
    Abstract311)      PDF(pc) (346KB)(364)       Save

    In this paper, we investigate the blow-up of the smooth solutions to the quantum Navier-Stokes-Landau-Lifshitz systems(QNSLL) in the domains $\Omega \subseteq \mathbb{R} ^n(n =1, 2)$. We prove that the smooth solutions to the QNSLL will blow up in finite time in the domains half-space $\mathbb{R} _+^n$, whole-space $\mathbb{R} ^n$ and ball. The paper also shows that the blow-up time of the smooth solutions in half-space or whole-space only depends on boundary conditions, while the the blow-up time of the smooth solutions in the ball depends on initial data and boundary conditions. In particular, the above conclusions are also valid for NSLL systems.

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    The General Inverse Bonnesen-Style Inequalities in $\mathbb{R}^n$
    Xu Dong,Yan Zhang,Chunna Zeng,Xingxing Wang
    Acta mathematica scientia,Series A    2022, 42 (3): 641-650.  
    Abstract260)   HTML12)    PDF(pc) (337KB)(260)       Save

    The isoperimetric problem plays an important role in integral geometry. In this paper we mainly investigate the inverse form of the isoperimetric inequality, i.e. the general inverse Bonnesen-type inequalities. The upper bounds of several new general isoperimetric genus are obtained. Futhermore, as corollaries, we get a series of classical inverse Bonnesen-type inequalities in the plane. Finally, the best estimate between the results of three upper bounds is given.

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    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.  
    Abstract224)   HTML20)    PDF(pc) (660KB)(448)       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.

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    The Bonnesen-type Inequalities for Plane Closed Curves
    Rui Bin,Xingxing Wang,Chunna Zeng
    Acta mathematica scientia,Series A    2022, 42 (6): 1601-1610.  
    Abstract212)   HTML9)    PDF(pc) (354KB)(230)       Save

    The isoperimetric inequality is one of the most classical geometric inequalities in differential geometry. The stability of isoperimetric genus can be characterized by Bonnesentype inequality and Bottema-type inequality. In this paper, via the method of differential geometry, Wirtinger inequality, Sachs inequality and divergence theorem and so on, we investigate the Bonnesen-type inequalities and Bottema-type inequalities for plane closed curves, and obtain a series of new Bonnesen-type inequalities and Bottema-type inequalities for curvature integration.

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    Approximate Optimality Conditions and Mixed Type Duality for a Class of Non-Convex Optimization Problems
    Jiaolang Wang,Donghui Fang
    Acta mathematica scientia,Series A    2022, 42 (3): 651-660.  
    Abstract201)   HTML4)    PDF(pc) (298KB)(175)       Save

    By using the properties of the Fréchet subdifferentials, we first introduce a new constraint qualification and then establish some approximate optimality conditions for the non-convex constrained optimization problem with objective function and/or constraint function being α-convex function. Moreover, some results for the weak duality, strong duality and converse-like duality theorems between this non-convex optimization problem and its mixed type dual problem are also given.

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    Similarity and Unitary Similarity of a Class of Upper Triangular Operator Matrices
    Liqiong Lin,Jiahua Que,Yunnan Zhang
    Acta mathematica scientia,Series A    2022, 42 (5): 1281-1293.  
    Abstract197)   HTML18)    PDF(pc) (268KB)(279)       Save

    This paper introduces a class of upper triangular operator matrices related to Cowen-Douglas operators, and studies its similarity on Banach spaces and its unitary similarity on Hilbert spaces.

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    Breather Wave Solutions, Lump Solutions and Semi-Rational Solutions of a Reduced (3+1)Dimensional Hirota Equation
    Chunmei Fang,Shoufu Tian
    Acta mathematica scientia,Series A    2022, 42 (3): 775-783.  
    Abstract196)   HTML1)    PDF(pc) (1085KB)(106)       Save

    In this paper, the long wave limit method is used to study the exact solutions of the (3+1)dimensional Hirota equation under dimensional reduction $z$=$x$. First, the bilinear form is constructed by using Bell polynomials. Based on the bilinear form, the $n$-order breather wave solutions are obtained under some parameter constraints on the $N$-order soliton solution. Secondly, by using the long wave limit method, high order lump wave solutions are obtained. Finally, the combined solutions of the first-order, second-order lump wave solutions and single solitary wave solutions are derived, i.e. semi-rational solutions. All the obtained solutions were analyzed with Maple software for physical characteristics.

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    Perturbations of Canonical Unitary Involutions Associated with Quantum Bernoulli Noises
    Nan Fan,Caishi Wang,Hong Ji
    Acta mathematica scientia,Series A    2022, 42 (4): 969-977.  
    Abstract186)   HTML4)    PDF(pc) (502KB)(200)       Save

    Quantum Bernoulli noises (QBN) are annihilation and creation operators acting on the space of square integrable Bernoulli functionals, which satisfy a canonical anti-commutation relation (CAR) in equal time and can play an important role in describing the environment of an open quantum system. In this paper, we address a type of perturbations of the canonical unitary involutions associated with QBN. We analyze these perturbations from a perspective of spectral theory and obtain exactly their spectra, which coincide with their point spectra. We also discuss eigenvectors of these perturbations from an algebraic point of view and unveil the structures of the subspaces consisting of their eigenvectors. Finally, as application, we consider the abstract quantum walks driven by these perturbations and obtain infinitely many invariant probability distributions of these walks.

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    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.  
    Abstract178)   HTML18)    PDF(pc) (508KB)(349)       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.

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    Complex Symmetry for a Class of Truncated Hankel Operators
    Liling Lai,Jinjin Liang,Yong Chen
    Acta mathematica scientia,Series A    2022, 42 (4): 961-968.  
    Abstract174)   HTML8)    PDF(pc) (293KB)(233)       Save

    The truncated Hankel operator is the compression to the model space of Hankel operator on the Hardy space. In this paper, the complex symmetry for a class of truncated Hankel operators is studied and the complete characterization is given. The obtained results show that, the complex symmetry of truncated Hankel operator may be related to the model space only, or to the model space and the symbol function of the operator both.

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    Robust Accessible Hyperbolic Repelling Sets
    Xiao Jianrong
    Acta mathematica scientia,Series A    2024, 44 (1): 1-11.  
    Abstract173)   HTML10)    PDF(pc) (800KB)(279)       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.

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    Dynamics of an Anthrax Epidemiological Model with Time Delay and Seasonality
    Tailei Zhang,Junli Liu,Mengjie Han
    Acta mathematica scientia,Series A    2022, 42 (3): 851-866.  
    Abstract169)   HTML3)    PDF(pc) (480KB)(125)       Save

    In this paper, we developed a time-delayed epidemiological model to describe the anthrax transmission, which incorporates seasonality and the incubation period of the animal population. The basic reproduction number $R_{0}$ can be obtained. It is shown that the threshold dynamics is completely determined by the basic reproduction number. If $R_{0}<1$, the disease-free periodic solution is globally attractive and the disease will die out; if $R_{0} >1$, then there exists at least one positive periodic solution and the disease persists. We further investigate the corresponding autonomous system, the global stability of the disease-free equilibrium and the positive equilibrium is established in terms of $[R_0]$. Numerical simulations are carried out to investigate the sensitivity of $R_0$ about the parameters, the effects of vaccination and carcass disposal on controlling the spread of anthrax is also analyzed.

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    α-Robust Optimal Investment Strategy for Target Benefit Pension Plans Under Default Risk
    Yuan Shi,Yongxia Zhao
    Acta mathematica scientia,Series A    2022, 42 (3): 943-960.  
    Abstract166)   HTML1)    PDF(pc) (560KB)(136)       Save

    This paper considers the optimal investment and benefit payment problem for target benefit pension plan with default risk and model uncertainty. We assume that pension funds are invested in a risk-free asset, a defaultable bond and a stock satisfied a constant elasticity of variance(CEV) model. The payment of pensions depends on the financial status of the plan, with risk sharing between different generations. At the same time, in order to protect the rights of pension holders who dies before retirement, the return of premiums clauses is added to the model. In addition, our model allows the pension manager to have different levels of ambiguity aversion, instead of only considering extremely ambiguity-averse attitude. Using the stochastic optimal control approach, we establish the Hamilton-Jacobi-Bellman equations for both the post-default case and the pre-default case, respectively. We derive the closed-form solutions for α-robust optimal investment strategies and optimal benefit payment adjustment strategies. Finally, numerical analyses illustrate the influence of financial market parameters on optimal control problems.

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    The Properties and Applications of the MP Weak Core Inverse
    Xiaoji Liu,Mengyue Liao,Hongwei Jin
    Acta mathematica scientia,Series A    2022, 42 (6): 1619-1632.  
    Abstract151)   HTML3)    PDF(pc) (338KB)(98)       Save

    In this paper, the concept of the Moore-Penrose weak Core inverse (MPWC inverse) is proposed based on the Moore-Penrose inverse and the weak Core inverse. It is described from algebraic and geometric perspectives respectively. The relationship between the MP weak Core inverse and the nonsingular bordered matrix is given. The expression of the MP weak Core inverse is given by using the Hartwig-Spindelböck decomposition and the Core-EP decomposition. The equivalence between the MP weak Core inverse of a matrix and EP matrix, the characterization and the perturbation analysis are given.

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    Locally Minimizing Solutions of a Two-component Ginzburg-Landau System
    Xiong Chen, Gao Qi
    Acta mathematica scientia,Series A    2023, 43 (2): 321-340.  
    Abstract149)   HTML9)    PDF(pc) (446KB)(411)       Save

    In this paper, we consider a Ginzburg-Landau functional for a complex vector order parameter $\Psi=[\psi_+, \psi_-]$. In particular, we consider entire solutions in all ${\Bbb R}^2$, which are obtained by blowing up around vortices. Among the entire solutions we distinguish those which are locally minimizing solutions, and we show that locally minimizing solutions must have degrees $n_\pm \in \{0, \pm1\}$. By studying the local structure of these solutions, we also show that one component of the solution vanishes, but the other does not, which describes the coreless vortex phenomenon in physics.

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    Two-Dimensional Infinite Square Well in Fractional Quantum Mechanics
    Yunjie Tan,Xiaohui Han,Jianping Dong
    Acta mathematica scientia,Series A    2022, 42 (4): 1018-1026.  
    Abstract147)   HTML2)    PDF(pc) (397KB)(105)       Save

    Fractional quantum mechanics is a generalization of standard quantum mechanics, which is described by fractional Schrödinger equation with fractional Riesz derivative operator. In this paper, we consider a free particle moving in a two-dimensional infinite square well, By using Lévy path integral method, the wave function and energy eigenvalue of the two-dimensional infinite square well are obtained. Then the perturbation expansion method is used to study the two-dimensional infinite square well with $\delta$ function, and the corresponding energy-dependent Green's function is obtained.

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    Existence of Positive Ground State Solutions for the Choquard Equation
    Xudong Shang,Jihui Zhang
    Acta mathematica scientia,Series A    2022, 42 (3): 749-759.  
    Abstract145)   HTML1)    PDF(pc) (355KB)(142)       Save

    In this paper we study the following nonlinear Choquard equation where $N \geq 3$, $\alpha \in (0, N)$, $I_{\alpha}$ is the Riesz potential, $V(x):\mathbb{R} ^{N} \rightarrow \mathbb{R} $ is a given potential function, and $F\in {\cal C}^{1}(\mathbb{R}, \mathbb{R})$ with $F'(s)=f(s)$. Under assumptions on $V$ and $f$, we do not require the $(AR)$ condition of $f$, the existence of ground state solutions are obtained via variational methods.

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    The Maximal Operator of Vilenkin-like System on Hardy Spaces
    Chuanzhou Zhang,Chaoyue Wang,Xueying Zhang
    Acta mathematica scientia,Series A    2022, 42 (5): 1294-1305.  
    Abstract144)   HTML4)    PDF(pc) (311KB)(140)       Save

    In this paper, we discuss the boundedness of maximal operator with respect to bounded Vilenkin-like system (or $\psi\alpha$ system) which is generalization of bounded Vilenkin system. We prove that when $0 < p <1/2$ the maximal operator $\tilde{\sigma}_p^*f=\sup\limits_{n\in {\Bbb N}}\frac{|\sigma_nf|}{(n+1)^{1/p-2}}$ is bounded from the martingale Hardy space $H_p$ to the space $L_p$, where $\sigma_nf$ is $n$-th Fej\'er mean with respect to bounded Vilenkin-like system. By a counterexample, we also prove that the maximal operator $\sup\limits_{n\in {\Bbb N}}\frac{|\sigma_nf|}{\varphi(n)}$ is not bounded from the martingale Hardy space $H_{p}$ to the space $L_{p,\infty}$ when $0 < p <1/2$ and $\mathop{\overline{\lim}}\limits_{n\rightarrow \infty}\frac{(n+1)^{1/p-2}}{\varphi(n)}=+\infty$.

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    Traveling Wave of a Reaction-Diffusion Dengue Epidemic Model with Time Delays
    Kai Wang,Hongyong Zhao
    Acta mathematica scientia,Series A    2022, 42 (4): 1209-1226.  
    Abstract143)   HTML3)    PDF(pc) (961KB)(130)       Save

    In this paper, we investigate the existence and nonexistence of traveling wave solution (TWS) for a reaction-diffusion dengue epidemic model with time delays. Firstly, by introducing an auxiliary system and combining with Schauder's fixed-point theorem, it is proved that when the basic reproduction number ${\cal R}_0>1$, $c>c_\ast$, the system admits a positive bounded monotone TWS. Secondly, when ${\cal R}_0>1$, $0<c<c_\ast$, by means of two-sided Laplace transform, the nonexistence of TWS is obtained. When ${\cal R}_0\leq1$, there is no TWS for any wave speed $c>0$ with the aid of comparison principle and contradictory arguments. Lastly, the effects of incubation period and individual diffusion on the threshold speed $c_\ast$ are studied theoretically and numerically. The conclusion shows that prolonging the length of incubation period or decreasing the individual diffusion will reduce the speed of disease transmission.

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    The Self-Adjointness and Dependence of Eigenvalues of Fourth-Order Differential Operator with Eigenparameters in the Boundary Conditions
    Wenwen Yan,Meizhen Xu
    Acta mathematica scientia,Series A    2022, 42 (3): 671-693.  
    Abstract140)   HTML1)    PDF(pc) (450KB)(188)       Save

    In this paper we consider the self-adjointness and the dependence of eigenvalues of a class of discontinuous fourth-order differential operator with eigenparameters in the boundary conditions of one endpoint. By constructing a linear operator T associated with problem in a suitable Hilbert space, the study of the above problem is transformed into the research of the operator in this space, and the self-adjointness of this operator T is proved. In addition, on the basis of the self-adjointness of the operator T, we show that the eigenvalues are not only continuously but also smoothly dependent on the parameters of the problem, and give the corresponding differential expressions. In particular, giving the Fréchet derivative of the eigenvalue with respect to the eigenparameter-dependent boundary condition coefficient matrix, and the first-order derivatives of the eigenvalue with respect to the left and right sides of the inner discontinuity point c.

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