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    On the Distribution of the Values of a Class of Arithmetical Functions
    SHAO Pin-tsung
    Chinese Quarterly Journal of Mathematics    1987, 2 (2): 27-43.  
    Abstract175)      PDF(pc) (895KB)(398)       Save
    对于数义在自然数集 N 上的数论函数(Arithmetical function)f(n), n\inN,取值可以是实数, 也可以是复数(一般为实数), 例如著名的 Euler 函数 \varphi(n)=\Sigma_{(a,n)=1,a<n}1,  除数函数τ(n)=\Sigma_{d/n}1,以及除数和函数σ(n)=\Sigma_{d/n}
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    Nested Alternating Direction Method of Multipliers to Low-Rank and Sparse-Column Matrices Recovery
    SHEN Nan , JIN Zheng-fen , WANG Qiu-yu
    Chinese Quarterly Journal of Mathematics    2021, 36 (1): 90-110.   DOI: 10.13371/j.cnki.chin.q.j.m.2021.01.007
    Abstract143)      PDF(pc) (427KB)(380)       Save
    The task of dividing corrupted-data into their respective subspaces can be well
    illustrated, both theoretically and numerically, by recovering low-rank and sparse-column
    components of a given matrix. Generally, it can be characterized as a matrix and a
    `2,1-norm involved convex minimization problem. However, solving the resulting problem
    is full of challenges due to the non-smoothness of the objective function. One of the
    earliest solvers is an 3-block alternating direction method of multipliers (ADMM) which
    updates each variable in a Gauss-Seidel manner. In this paper, we present three variants
    of ADMM for the 3-block separable minimization problem. More preciously, whenever
    one variable is derived, the resulting problems can be regarded as a convex minimization
    with 2 blocks, and can be solved immediately using the standard ADMM. If the inner
    iteration loops only once, the iterative scheme reduces to the ADMM with updates in a
    Gauss-Seidel manner. If the solution from the inner iteration is assumed to be exact, the
    convergence can be deduced easily in the literature. The performance comparisons with a
    couple of recently designed solvers illustrate that the proposed methods are effective and
    competitive.
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    On Some Recent Progress in Complex Geometry|the Area Related to Homogeneous Manifolds
    GUAN Daniel
    Chinese Quarterly Journal of Mathematics    2020, 35 (2): 111-144.   DOI: 10.13371/j.cnki.chin.q.j.m.2020.02.001
    Abstract440)      PDF(pc) (1154KB)(367)       Save
    In this article, we give a survey of some progress of the complex geometry, mostly related to the Lie group actions on compact complex manifolds and complex homogeneous spaces in the last thirty years. In particular, we explore some works in the special area in Di erential Geometry, Lie Group and Complex Homogeneous Space. Together with the special area in nonlinear analysis on complex manifolds, they are the two major aspects of my research interests.
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    Buildings and Groups III
    LAI King-fai
    Chinese Quarterly Journal of Mathematics    2021, 36 (1): 1-31.   DOI: 10.13371/j.cnki.chin.q.j.m.2021.01.001
    Abstract269)      PDF(pc) (533KB)(364)       Save
    This is the third part of a pedagogical introduction to the theory of buildings of Jacques Tits. We describe the construction and properties of the Bruhat-Tits building of a reductive group over a local field.
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    Well-Posedness for Timoshenko System with Thermodiffusion Effects and Delay
    QIN Yu-ming, HAN Ning
    Chinese Quarterly Journal of Mathematics    2022, 37 (1): 1-9.   DOI: 10.13371/j.cnki.chin.q.j.m.2022.01.001
    Abstract141)      PDF(pc) (293KB)(349)       Save
     In this paper, we study the well-posedness for the thermoelastic Timoshenko system with a constant delay and mass diffusion effects. Heat and mass exchange with the environment during thermodiffusion in Timoshenko beam. The C 0 -semigroup theory will be used to prove the well-posedness of the considered problem.
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    Dyons of Unit Topological Charges in Gauged Skyrme Model
    WU Zhong-lin, LI Dong-ya
    Chinese Quarterly Journal of Mathematics    2019, 34 (2): 152-170.   DOI: 10.13371/j.cnki.chin.q.j.m.2019.02.004
    Abstract58)      PDF(pc) (609KB)(328)       Save
    Dyons are an important family of topological solitons carrying both electric and magnetic charges and the presence of a nontrivial temporal component of the gauge field essential for the existence of electricity often makes the analysis of the underlying nonlinear equations rather challenging since the governing action functional assumes an indefinite form. In this work, developing a constrained variational technique, We establish an existence theorem for the dyon solitons in a Skyrme model coupled with SO(3)-gauge fields, formulated by Brihaye, Kleihaus, and Tchrakian. These solutions carry unit monopole and Skyrme charges. 
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    A Posterior Estimates in the Finite Element Methods
    E Wei-nan, MU Mo, HUANG Hong-ci
    Chinese Quarterly Journal of Mathematics    1988, 3 (1): 97-107.  
    Abstract432)      PDF(pc) (588KB)(326)       Save
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    General Energy Decay of Solutions for A Wave Equation with Nonlocal Nonlinear Damping and Source Terms
    ZHANG Hong-wei, LI Dong-hao, HU Qing-ying
    Chinese Quarterly Journal of Mathematics    2020, 35 (3): 302-310.   DOI: 10.13371/j.cnki.chin.q.j.m.2020.03.005
    Abstract144)      PDF(pc) (473KB)(317)       Save
    We consider a wave equation with nonlocal nonlinear damping and source terms. We prove a general energy decay property for solutions by constructing a stable set and using the multiplier technique. The main difficult is how to handle with the nonlocal nonlinear damping term. Our result extends and improves the result in the literature such as the work by Jorge Silva and Narciso(Evolution Equation and Control Theory, 2017(6):437-470) and Narciso(Evolution Equations and Control Theory, 2020, 9(2): 487-508).
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    EEG Feature Learning Model Based on Intrinsic Time-Scale Decomposition and Adaptive Huber Loss
    YANG Li-jun, JIANG Shu-yue, WEI Xiao-ge , XIAO Yun-hai
    Chinese Quarterly Journal of Mathematics    2022, 37 (3): 281-300.   DOI: 10.13371/j.cnki.chin.q.j.m.2022.03.006
    Abstract121)      PDF(pc) (538KB)(316)       Save
    According to the World Health Organization, about 50 million people world-
    wide suffer from epilepsy. The detection and treatment of epilepsy face great challenges.
    Electroencephalogram (EEG) is a significant research object widely used in diagnosis and
    treatment of epilepsy. In this paper, an adaptive feature learning model for EEG signals
    is proposed, which combines Huber loss function with adaptive weight penalty term.
    Firstly, each EEG signal is decomposed by intrinsic time-scale decomposition. Secondly,
    the statistical index values are calculated from the instantaneous amplitude and frequency
    of every component and fed into the proposed model. Finally, the discriminative features
    learned by the proposed model are used to detect seizures. Our main innovation is to
    consider a highly flexible penalization based on Huber loss function, which can set different
    weights according to the influence of different features on epilepsy detection. Besides, the
    new model can be solved by proximal alternating direction multiplier method, which can
    effectively ensure the convergence of the algorithm. The performance of the proposed
    method is evaluated on three public EEG datasets provided by the Bonn University,
    Childrens Hospital Boston-Massachusetts Institute of Technology, and Neurological and
    Sleep Center at Hauz Khas, New Delhi(New Delhi Epilepsy data). The recognition
    accuracy on these two datasets is 98% and 99.05%, respectively, indicating the application
    value of the new model.
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    Finite Difference Methods for the Time Fractional Advection-diffusion Equation
    MA Yan, MUSBAH F.S.
    Chinese Quarterly Journal of Mathematics    2019, 34 (3): 259-273.   DOI: 10.13371/j.cnki.chin.q.j.m.2019.03.004
    Abstract98)      PDF(pc) (559KB)(302)       Save
    In this paper, three implicit finite difference methods are developed to solve one dimensional time fractional advection-diffusion equation. The fractional derivative is treated by applying right shifted Gr¨unwald-Letnikov formula of order α∈(0, 1). We investigate the stability analysis by using von Neumann method with mathematical induction and prove that these three proposed methods are unconditionally stable. Numerical results are presented to demonstrate the effectiveness of the schemes mentioned in this paper.
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    Buildings and Groups II
    CHAO Kuok Fai, LAI King Fai
    Chinese Quarterly Journal of Mathematics    2020, 35 (3): 221-254.   DOI: 10.13371/j.cnki.chin.q.j.m.2020.03.001
    Abstract276)      PDF(pc) (1238KB)(285)       Save
    This is the second part of a pedagogical introduction to the theory of buildings of Jacques Tits. We define a(B,N) pair and construct a building out of it. Then we give a description of Chevalley groups, their(B,N) pair and the associated buildings. We illustrates this theory with many examples from classical groups. 
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    Strongly α-Refexive Rings Relative to a Monoid
    PENG Zhai-ming, GU Qin-qin, ZHANG Rui-rui
    Chinese Quarterly Journal of Mathematics    2018, 33 (3): 260-271.   DOI: 10.13371/j.cnki.chin.q.j.m.2018.03.004
    Abstract69)      PDF(pc) (445KB)(264)       Save
    For a monoid M and an endomorphism α of a ring R, we introduce the notion of strongly M-α-reflexive rings and study its properties. For an u.p.-monoid M and a right Ore ring R with its classical right quotient ring Q, we prove that R is strongly M-α-reflexive if and only if Q is strongly M-α-reflexive, where R is α-rigid, α is an epimorphism of R. The relationship between some special subrings of upper triangular matrix rings and strongly M-α-reflexive rings is also investigated. Several known results similar to strongly M-α-reversible rings are obtained. 
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    Vacuum Problem for The System of One Dimensional Isentropic Flow
    Li Da-qian, Zhao Yan-chun
    Chinese Quarterly Journal of Mathematics    1986, 1 (1): 41-46.  
    Abstract88)      PDF(pc) (373KB)(259)       Save
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    Building and Groups I
    LAI King-fai, LIANG Zhi-bin
    Chinese Quarterly Journal of Mathematics    2020, 35 (1): 1-28.   DOI: 10.13371/j.cnki.chin.q.j.m.2020.01.001
    Abstract152)      PDF(pc) (913KB)(259)       Save
    This is a pedagogical introduction to the theory of buildings 〇£ Jacques Tits and to some applications of this theory. This paper has 4 parts. In the first part we discuss incidence geometry, Coxeter systems and give two definitions of buildings. We study in the second part the spherical and affine buildings of Chevalley groups. In the third part we deal with Bruhat-Tits theory of reductive groups over local fields. Finally we discuss the construction of the p-adic flag manifolds.
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    Sparse Reduced-Rank Regression with Outlier Detection
    LIANG Bing-jie
    Chinese Quarterly Journal of Mathematics    2021, 36 (3): 275-287.   DOI: 10.13371/j.cnki.chin.q.j.m.2021.03.006
    Abstract85)      PDF(pc) (622KB)(257)       Save
     Based on the multivariate mean-shift regression model, we propose a new
    sparse reduced-rank regression approach to achieve low-rank sparse estimation and outlier
    detection simultaneously. A sparse mean-shift matrix is introduced in the model to indicate
    outliers. The rank constraint and the group-lasso type penalty for the coefficient matrix
    encourage the low-rank row sparse structure of coefficient matrix and help to achieve
    dimension reduction and variable selection. An algorithm is developed for solving our
    problem. In our simulation and real-data application, our new method shows competitive
    performance compared to other methods.
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    Finite Di erence Method for Riesz Space Fractional Advection-dispersion Equation with Fractional Robin Boundary Condition
    LIN Hai-xin, FANG Shao-mei,
    Chinese Quarterly Journal of Mathematics    2020, 35 (3): 278-289.   DOI: 10.13371/j.cnki.chin.q.j.m.2020.03.003
    Abstract151)      PDF(pc) (611KB)(252)       Save
    In this paper, a Riesz space fractional advection-dispersion equation with fractional Robin boundary condition is considered. By applying the fractional central difference formula and the weighted and shifted Gru¨nwald-Letnikov formula, we derive a weighted implicit finite difference scheme with accuracy O(?t2+ h2). The solvability,stability, and convergence of the proposed numerical scheme are proved. A numerical example is presented to confirm the accuracy and efficiency of the scheme. 
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    A Finite Volume Unstructured Mesh Method for Fractional-in-space Allen-Cahn Equation
    CHEN Ai-min, , LIU Fa-wang
    Chinese Quarterly Journal of Mathematics    2017, 32 (4): 345-354.   DOI: 10.13371/j.cnki.chin.q.j.m.2017.04.002
    Abstract79)      PDF(pc) (761KB)(250)       Save

    Fractional-in-space Allen-Cahn equation containing a very strong nonlinear source term and small perturbation shows metastability and a quartic double well potential.Using a finite volume unstructured triangular mesh method, the present paper solves the twodimensional fractional-in-space Allen-Cahn equation with homogeneous Neumann boundary condition on different irregular domains. The efficiency of the method is presented through numerical computation of the two-dimensional fractional-in-space Allen-Cahn equation on different domains. 

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    On Intersection Multiplicity of Algebraic Curves
    LIANG Hong-Chang
    Chinese Quarterly Journal of Mathematics    2019, 34 (1): 14-20.   DOI: 10.13371/j.cnki.chin.q.j.m.2019.01.002
    Abstract101)      PDF(pc) (306KB)(250)       Save
    In this paper, we study the intersection multiplicity of algebraic curves at a point both in R~2 and in real projective plane P~2. We introduce the fold point of curves and provide conditions for the relations between the intersection multiplicity of curves at a point and the folds of the point. 
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    On One-Dimensionsl Dynamics
    ZHOU Zuo-ling
    Chinese Quarterly Journal of Mathematics    1988, 3 (1): 42-65.  
    Abstract119)      PDF(pc) (1556KB)(246)       Save
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    Blow-Up Result for a Semi-Linear Wave Equation with a Nonlinear Memory Term of Derivative Type
    OUYANG Bai-ping, XIAO Sheng-zhong
    Chinese Quarterly Journal of Mathematics    2021, 36 (3): 235-243.   DOI: 10.13371/j.cnki.chin.q.j.m.2021.03.002
    Abstract130)      PDF(pc) (330KB)(241)       Save
    In this paper, we study the blow-up of solutions to a semi-linear wave equation with a nonlinear memory term of derivative type. By using methods of an iteration argument and differential inequalities, we obtain the blow-up result for the semi-linear wave equation when the exponent of p is under certain conditions. Meanwhile, we derive an upper bound of the lifespan of solutions to the Cauchy problem for the semi-linear wave equation.
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