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POINTWISE ESTIMATE OF SOLUTIONS OF ISENTROPIC NMIER-STOKES EQUATIONS IN EVEN SPACE-DIMENSIONS 被引量:8
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作者 徐红梅 王维克 《Acta Mathematica Scientia》 SCIE CSCD 2001年第3期417-427,共11页
This paper is concerned with the dissipation of solutions of the isentropic Navier-Stokes equations in even and bigger than two multi-dimensions. Pointwise estimates of the time-asymptotic shape of the solutions are o... This paper is concerned with the dissipation of solutions of the isentropic Navier-Stokes equations in even and bigger than two multi-dimensions. Pointwise estimates of the time-asymptotic shape of the solutions are obtained and the generalized Huygan's principle is exhibited. The approch of the paper is based on the detailed analysis of the Green function of Iinearized system. This is used to study the coupling of nonlinear diffesion waves. 展开更多
关键词 Isentropic Navier-Stokes equation multi-dimensions Green's function pointwise estimate
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THE POINTWISE ESTIMATES OF SOLUTIONS FOR A NONLINEAR CONVECTION DIFFUSION REACTION EQUATION 被引量:1
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作者 刘国威 《Acta Mathematica Scientia》 SCIE CSCD 2017年第1期79-96,共18页
This paper studies the time asymptotic behavior of solutions for a nonlinear convection diffusion reaction equation in one dimension.First,the pointwise estimates of solutions are obtained,furthermore,we obtain the op... This paper studies the time asymptotic behavior of solutions for a nonlinear convection diffusion reaction equation in one dimension.First,the pointwise estimates of solutions are obtained,furthermore,we obtain the optimal Lp,1≤ p ≤ +∞,convergence rate of solutions for small initial data.Then we establish the local existence of solutions,the blow up criterion and the sufficient condition to ensure the nonnegativity of solutions for large initial data.Our approach is based on the detailed analysis of the Green function of the linearized equation and some energy estimates. 展开更多
关键词 convection diffusion reaction equation pointwise estimate Green function energy method
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POINTWISE ESTIMATES OF SOLUTIONS FOR THE NONLINEAR VISCOUS WAVE EQUATION IN EVEN DIMENSIONS 被引量:1
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作者 Nianying LI 《Acta Mathematica Scientia》 SCIE CSCD 2020年第4期1001-1019,共19页
In this article,we study the pointwise estimates of solutions to the nonlinear viscous wave equation in even dimensions(n≥4).We use the Green’s function method.Our approach is on the basis of the detailed analysis o... In this article,we study the pointwise estimates of solutions to the nonlinear viscous wave equation in even dimensions(n≥4).We use the Green’s function method.Our approach is on the basis of the detailed analysis of the Green’s function of the linearized system.We show that the decay rates of the solution for the same problem are different in even dimensions and odd dimensions.It is shown that the solution exhibits a generalized Huygens principle. 展开更多
关键词 viscous wave equation pointwise estimate even dimensions
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Pointwise Estimate of Solutions to the Three-Dimensional Compressible Magnetohydrodynamic Equations 被引量:1
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作者 ZHOU Fang 《Wuhan University Journal of Natural Sciences》 CAS CSCD 2015年第3期185-192,共8页
This paper is devoted to the pointwise estimate of solutions for the initial value problem to the three-dimensional compressible magnetohydrodynamic equations, which models the dynamics of compressible quasi-neutrally... This paper is devoted to the pointwise estimate of solutions for the initial value problem to the three-dimensional compressible magnetohydrodynamic equations, which models the dynamics of compressible quasi-neutrally ionized fluids under the influence of electromagnetic fields. Based on the detailed analysis of the Green function of the linearized system, we obtain the pointwise estimates of smooth solutions when the initial data is sufficiently small with the algebraic decay to the constant equilibrium. As the by-product, we also show the corresponding pL-estimates of the smooth solutions. 展开更多
关键词 compressible MHD equations pointwise estimate Green function pL-estimates
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THE POINTWISE ESTIMATES TO SOLUTIONS FOR 1-DIMENSIONAL LINEAR THERMO-VISCO-ELASTIC SYSTEM
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作者 郝兴文 彭少玉 《Acta Mathematica Scientia》 SCIE CSCD 2011年第4期1259-1271,共13页
In this paper, we study the linear thermo-visco-elastic system in one-dimensional space variable. The mathematical model is a hyperbolic-parabolic partial differential system. The solutions of the system show some dec... In this paper, we study the linear thermo-visco-elastic system in one-dimensional space variable. The mathematical model is a hyperbolic-parabolic partial differential system. The solutions of the system show some decay property due to the parabolicity. Based on detailed analysis on the Green function of the system, the pointwise estimates of the solutions are obtained, from which the generalized Huygens’ principle is shown. 展开更多
关键词 thermo-visco-elastic system Fourier transform Green function pointwise estimate Huygens’ principle
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Unconditional and Optimal Pointwise Error Estimates of Finite Difference Methods for the Two-Dimensional Complex Ginzburg-Landau Equation
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作者 Yue CHENG Dongsheng TANG 《Journal of Mathematical Research with Applications》 CSCD 2024年第2期248-268,共21页
In this paper,we give improved error estimates for linearized and nonlinear CrankNicolson type finite difference schemes of Ginzburg-Landau equation in two dimensions.For linearized Crank-Nicolson scheme,we use mathem... In this paper,we give improved error estimates for linearized and nonlinear CrankNicolson type finite difference schemes of Ginzburg-Landau equation in two dimensions.For linearized Crank-Nicolson scheme,we use mathematical induction to get unconditional error estimates in discrete L^(2)and H^(1)norm.However,it is not applicable for the nonlinear scheme.Thus,based on a‘cut-off’function and energy analysis method,we get unconditional L^(2)and H^(1)error estimates for the nonlinear scheme,as well as boundedness of numerical solutions.In addition,if the assumption for exact solutions is improved compared to before,unconditional and optimal pointwise error estimates can be obtained by energy analysis method and several Sobolev inequalities.Finally,some numerical examples are given to verify our theoretical analysis. 展开更多
关键词 complex Ginzburg-Landau equation finite difference method unconditional convergence optimal estimates pointwise error estimates
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ON POINTWISE ESTIMATE FOR GAMMA OPERATORS
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作者 Guo Shunsheng and Qi Qiulan (Hebei Normal University, China) 《Approximation Theory and Its Applications》 2002年第3期93-98,共6页
For linear combinations of Gamma operators, if 0<a<2r, 1/2-1/2r≤λ≤1. or 0≤λ≤1/2-1/2r(r≥2),0 <a<r+1/1-λ, we obtain an equivalent theorem with ω(?)(f,t) instead of ω(?)(f,t), where ω(?)(f,t) is th... For linear combinations of Gamma operators, if 0<a<2r, 1/2-1/2r≤λ≤1. or 0≤λ≤1/2-1/2r(r≥2),0 <a<r+1/1-λ, we obtain an equivalent theorem with ω(?)(f,t) instead of ω(?)(f,t), where ω(?)(f,t) is the Ditzian-Totik moduli of smoothness. 展开更多
关键词 ON pointwise estimate FOR GAMMA OPERATORS MATH ZR
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GLOBAL EXISTENCE AND POINTWISE ESTIMATES OF SOLUTIONS TO GENERALIZED KURAMOTO-SIVASHINSKY SYSTEM IN MULTI-DIMENSIONS
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作者 Yingshu ZHANG Lang LI Shaomei FANG 《Acta Mathematica Scientia》 SCIE CSCD 2019年第1期180-194,共15页
The Cauchy problem of the generalized Kuramoto-Sivashinsky equation in multidimensions(n ≥ 3) is considered. Based on Green's function method, some ingenious energy estimates are given. Then the global existence ... The Cauchy problem of the generalized Kuramoto-Sivashinsky equation in multidimensions(n ≥ 3) is considered. Based on Green's function method, some ingenious energy estimates are given. Then the global existence and pointwise convergence rates of the classical solutions are established. Furthermore, the L^p convergence rate of the solution is obtained. 展开更多
关键词 Kuramoto-Sivashinsky equation global EXISTENCE pointwise estimates Green’s function METHOD energy METHOD
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Pointwise Estimates on Travelling Wave Solution of the Scalar Viscous Conservation Laws
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作者 Fu Yu-xia, Wang Wei-keSchool of Mathematics and Statistics, Wuhan University, Wuhan 430072, Hubei,China 《Wuhan University Journal of Natural Sciences》 CAS 2003年第02A期335-341,共7页
This paper research on the pointwise behavior of perturbations from a viscous shock solution to a scalar viscous conservation law by introducing an approximate Green’s function. The authors obtain not only the pointw... This paper research on the pointwise behavior of perturbations from a viscous shock solution to a scalar viscous conservation law by introducing an approximate Green’s function. The authors obtain not only the pointwise decay of the perturbation and but also the high derivative of it. Stability in anyL(p≥1) norm is a direct consequence. 展开更多
关键词 scalar viscous conservation law travelling wave approximate Green’s function pointwise decay
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Pointwise Estimates for Solutions to a System of Radiating Gas
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作者 Shikuan Mao Yongqin Liu 《International Journal of Modern Nonlinear Theory and Application》 2013年第3期186-193,共8页
In this paper we focus on the initial value problem of a hyperbolic-elliptic coupled system in multi-dimensional space of a radiating gas. By using the method of Green function combined with Fourier analysis, we obtai... In this paper we focus on the initial value problem of a hyperbolic-elliptic coupled system in multi-dimensional space of a radiating gas. By using the method of Green function combined with Fourier analysis, we obtain the pointwise decay estimates of solutions to the problem. 展开更多
关键词 Radiating GAS INITIAL VALUE Problem pointwise estimateS
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Pointwise Estimate of Cahn-Hilliard Equation with Inertial Term in R^(3)
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作者 XU Hongmei ZHU Yue 《Wuhan University Journal of Natural Sciences》 CAS CSCD 2022年第5期361-366,共6页
Cauchy problem of Cahn-Hilliard equation with inertial term in three-dimensional space is considered.Using delicate analysis of its Green function and its convolution with nonlinear term,pointwise decay rate is obtained.
关键词 Cahn-Hilliard equation with inertial term Green function pointwise decay
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The Volume Estimates of Geodesic Balls on Finsler Gradient Ricci Solitons
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作者 CHENG Xinyue LIANG Zirui NI Qihui 《数学进展》 北大核心 2025年第6期1357-1367,共11页
In this paper,we study and characterize the volume estimates of geodesic balls on Finsler gradient Ricci solitons.We get the upper bounds on the volumes of geodesic balls of all three kinds of Finsler gradient Ricci s... In this paper,we study and characterize the volume estimates of geodesic balls on Finsler gradient Ricci solitons.We get the upper bounds on the volumes of geodesic balls of all three kinds of Finsler gradient Ricci solitons under certain condition about the Laplacian of thedistance function. 展开更多
关键词 Finsler metric measure manifold weighted Ricci curvature gradient Ricci soliton geodesic ball volume estimate
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STRICHARTZ AND SMOOTHING ESTIMATES FOR DISPERSIVE SEMI-GROUP e^(-itP(D)) IN WEIGHTED L^(2) SPACES AND THEIR APPLICATIONS
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作者 Jiecheng CHEN Shaolei RU Chenjing WU 《Acta Mathematica Scientia》 2025年第2期401-415,共15页
Combining TT* argument and bilinear interpolation,this paper obtains the Strichartz and smoothing estimates of dispersive semigroup e^(-itP(D)) in weighted L^(2) spaces.Among other things,we recover the results in[1].... Combining TT* argument and bilinear interpolation,this paper obtains the Strichartz and smoothing estimates of dispersive semigroup e^(-itP(D)) in weighted L^(2) spaces.Among other things,we recover the results in[1].Moreover,the application of these results to the well-posedness of some equations are shown in the last section. 展开更多
关键词 Strichartz estimates smoothing estimates Morrey-Campanato class weighted L^(2)spaces WELL-POSEDNESS
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ASYMPTOTIC STABILITY OF COUETTE FLOW WITH NAVIER-SLIP BOUNDARY CONDITIONS FOR 2-D BOUSSINESQ SYSTEM VIA RESOLVENT ESTIMATE
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作者 Gaofeng WANG 《Acta Mathematica Scientia》 2025年第5期1752-1773,共22页
In this paper,we study the nonlinear stability problem for the two-dimensional Boussinesq system around the Couette flow in a finite channel with Navier-slip boundary condition for the velocity and Dirichlet boundary ... In this paper,we study the nonlinear stability problem for the two-dimensional Boussinesq system around the Couette flow in a finite channel with Navier-slip boundary condition for the velocity and Dirichlet boundary condition for the temperature with small viscosityνand small thermal diffusionμ.We establish that if the initial perturbation velocity and initial perturbation temperature satisfy ||u_(0)||H^(2)≤ε_(0) min{μ,ν}1/2, and ||θ_(0)||H^(1)+|||D_(x)|^(1/3)θ_(0)||H^(1)+|||D_(x)|^(1/3)θ_(0)||_(H^(1))≤εi min{μ,ν}^(5/6),for some smallε0 andε1 independent ofμ,ν,then the solution of the two-dimensional NavierStokes Boussinesq system does not transition away from the Couette flow for any time. 展开更多
关键词 stability threshold Couette flow resolvent estimates
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Rock discontinuity extraction from 3D point clouds using pointwise clustering algorithm
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作者 Xiaoyu Yi Wenxuan Wu +2 位作者 Wenkai Feng Yongjian Zhou Jiachen Zhao 《Journal of Rock Mechanics and Geotechnical Engineering》 2025年第7期4429-4444,共16页
Recognizing discontinuities within rock masses is a critical aspect of rock engineering.The development of remote sensing technologies has significantly enhanced the quality and quantity of the point clouds collected ... Recognizing discontinuities within rock masses is a critical aspect of rock engineering.The development of remote sensing technologies has significantly enhanced the quality and quantity of the point clouds collected from rock outcrops.In response,we propose a workflow that balances accuracy and efficiency to extract discontinuities from massive point clouds.The proposed method employs voxel filtering to downsample point clouds,constructs a point cloud topology using K-d trees,utilizes principal component analysis to calculate the point cloud normals,and employs the pointwise clustering(PWC)algorithm to extract discontinuities from rock outcrop point clouds.This method provides information on the location and orientation(dip direction and dip angle)of the discontinuities,and the modified whale optimization algorithm(MWOA)is utilized to identify major discontinuity sets and their average orientations.Performance evaluations based on three real cases demonstrate that the proposed method significantly reduces computational time costs without sacrificing accuracy.In particular,the method yields more reasonable extraction results for discontinuities with certain undulations.The presented approach offers a novel tool for efficiently extracting discontinuities from large-scale point clouds. 展开更多
关键词 Rock mass discontinuity 3D point clouds pointwise clustering(PWC)algorithm Modified whale optimization algorithm(MWOA)
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Space and time estimates of second gradient thermal problems
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作者 J.R.FERNÁNDEZ V.PATA R.QUINTANILLA 《Applied Mathematics and Mechanics(English Edition)》 2025年第7期1403-1416,共14页
We consider the space and time decays of certain problems within the second gradient thermal law.Notably,for this thermal theory,the exponential time decay is precluded.First,the time estimates of polynomial type are ... We consider the space and time decays of certain problems within the second gradient thermal law.Notably,for this thermal theory,the exponential time decay is precluded.First,the time estimates of polynomial type are obtained for both the thermal equation and the one-dimensional thermoelastic system,where the impossibility of localization with respect to time is also established.Then,the space estimates are deduced for the multidimensional thermoelastic problem,which allow to show the exponential decay of the energy. 展开更多
关键词 second gradient theory THERMOELASTICITY spatial estimate polynomial decay
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The estimation method is the primary source of uncertainty in cropland nitrate leaching estimates in China
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作者 Xingshuai Tian Huitong Yu +4 位作者 Jiahui Cong Yulong Yin Kai He Zihan Wang Zhenling Cui 《Journal of Integrative Agriculture》 2025年第6期2425-2437,共13页
Cropland nitrate leaching is the major nitrogen(N) loss pathway, and it contributes significantly to water pollution. However, cropland nitrate leaching estimates show great uncertainty due to variations in input data... Cropland nitrate leaching is the major nitrogen(N) loss pathway, and it contributes significantly to water pollution. However, cropland nitrate leaching estimates show great uncertainty due to variations in input datasets and estimation methods. Here, we presented a re-evaluation of Chinese cropland nitrate leaching, and identified and quantified the sources of uncertainty by integrating three cropland area datasets, three N input datasets, and three estimation methods. The results revealed that nitrate leaching from Chinese cropland averaged 6.7±0.6 Tg N yr^(-1)in 2010, ranging from 2.9 to 15.8 Tg N yr^(-1)across 27 different estimates. The primary contributor to the uncertainty was the estimation method, accounting for 45.1%, followed by the interaction of N input dataset and estimation method at 24.4%. The results of this study emphasize the need for adopting a robust estimation method and improving the compatibility between the estimation method and N input dataset to effectively reduce uncertainty. This analysis provides valuable insights for accurately estimating cropland nitrate leaching and contributes to ongoing efforts that address water pollution concerns. 展开更多
关键词 cropland nitrate leaching UNCERTAINTY cropland area nitrogen input estimation method
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Asymptotically Exact a Posteriori Error Estimates for Non-Symmetric Eigenvalue Problems
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作者 Jun ZHANG Jiayu HAN 《Journal of Mathematical Research with Applications》 2025年第3期411-426,共16页
This paper is devoted to the Polynomial Preserving Recovery (PPR) based a posteriori error analysis for the second-order elliptic non-symmetric eigenvalue problem. An asymptotically exact a posteriori error estimator ... This paper is devoted to the Polynomial Preserving Recovery (PPR) based a posteriori error analysis for the second-order elliptic non-symmetric eigenvalue problem. An asymptotically exact a posteriori error estimator is proposed for solving the convection-dominated non-symmetric eigenvalue problem with non-smooth eigenfunctions or multiple eigenvalues. Numerical examples confirm our theoretical analysis. 展开更多
关键词 Polynomial Preserving Recovery non-symmetric eigenvalue problem a posteriori error estimates
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Estimating the final fatalities using early reported death count from the 2023 Kahramanmaras,Türkiye,M_(S) 8.0-7.9 earthquake doublet and revising the estimates over time
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作者 Yan Liu Zitao Wang Xuemin Zhang 《Earthquake Research Advances》 2025年第2期5-12,共8页
Earthquakes can cause significant damage and loss of life,necessitating immediate assessment of the resulting fatalities.Rapid assessment and timely revision of fatality estimates are crucial for effective emergency d... Earthquakes can cause significant damage and loss of life,necessitating immediate assessment of the resulting fatalities.Rapid assessment and timely revision of fatality estimates are crucial for effective emergency decisionmaking.This study using the February 6,2023,M_(S)8.0 and M_(S)7.9 Kahramanmaras,Türkiye earthquakes as an example to estimate the ultimate number of fatalities.An early Quick Rough Estimate(QRE)based on the number of deaths reported by the Disaster and Emergency Management Presidency of Türkiye(AFAD)is conducted,and it dynamically adjusts these estimates as new data becomes available.The range of estimates of the final number of deaths can be calculated as 31384–56475 based on the"the QRE of the second day multiplied by 2–3" rule,which incorporates the reported final deaths 50500.The Quasi-Linear and Adaptive Estimation(QLAE)method adaptively adjusts the final fatality estimate within two days and predicts subsequent reported deaths.The correct order of magnitude of the final death toll can be estimated as early as 13 hr after the M_(S)8.0 earthquake.In addition,additional earthquakes such as May 12,2008,M_(S)8.1 Wenchuan earthquake(China),September 8,2023,M_(S)7.2 Al Haouz earthquake(Morocco),November 3,2023,M_(S)5.8 Mid-Western Nepal earthquake,December 18,2023,M_(S)6.1 Jishishan earthquake(China),January 1,2024,M_(S)7.2 Noto Peninsula earthquake(Japan)and August 8,2023,Maui,Hawaii,fires are added again to verified the correctness of the model.The fatalities from the Maui fires are found to be approximately equivalent to those resulting from an M_(S)7.4 earthquake.These methods complement existing frameworks such as Quake Loss Assessment for Response and Mitigation(QLARM)and Prompt Assessment of Global. 展开更多
关键词 Kahramanmaras earthquake Earthquake fatality Human loss estimates Seismic risk 2023 Maui fires
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THE A PRIORI ESTIMATES FOR A CLASS OF GENERAL HESSIAN QUOTIENT TYPE EQUATIONS
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作者 Ni XIANG Yuni XIONG Jingyi YAO 《Acta Mathematica Scientia》 2025年第3期867-884,共18页
In this paper, we derive the a priori estimates for a class of more general (k, l)-Hessian quotient type equations involving u and Du on the right hand function. As an application we prove the Liouville theorem depend... In this paper, we derive the a priori estimates for a class of more general (k, l)-Hessian quotient type equations involving u and Du on the right hand function. As an application we prove the Liouville theorem depending on Pogorelov type estimates. On the other hand, we obtain the existence and uniqueness of the k-admissible solution for these general equations with the Neumann boundary condition, based on some growth conditions for the right hand function. 展开更多
关键词 Hessian quotient type equations the a priori estimates Neumann problems Liouville Theorem
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