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RESEARCH ANNOUNCEMENTS Sharp Conditions of Global Existence for Klein-Gordon-Zakharov Equations in Three Space Dimensions 被引量:5
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作者 张健 甘在会 《数学进展》 CSCD 北大核心 2005年第2期241-244,共4页
1 Introduction In the present paper, we consider the Cauchy problem of the Klein-Gordon-Zakharov equations with different propagation speeds in three space dimensions:
关键词 dimensionS RESEARCH global SHARP Space for
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Estimate on the Dimension of Global Attractor for Nonlinear Higher-Order Coupled Kirchhoff Type Equations 被引量:3
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作者 Guoguang Lin Lingjuan Hu 《Advances in Pure Mathematics》 2018年第1期11-24,共14页
In this paper, we investigate the finite dimensions of the global attractor for nonlinear higher-order coupled Kirchhoff type equations with strong linear damping in Hilbert spaces E0?and E1. Under the appropriate ass... In this paper, we investigate the finite dimensions of the global attractor for nonlinear higher-order coupled Kirchhoff type equations with strong linear damping in Hilbert spaces E0?and E1. Under the appropriate assumptions, we acquire a precise estimate of the upper bound for its Hausdorff and Fractal dimensions. 展开更多
关键词 HIGHER-ORDER Kirchhoff-Type EQUATIONS global Attractor Hausdorff dimension Fractal dimension
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The Estimates of the Upper Bounds of Hausdorff Dimensions for the Global Attractor for a Class of Nonlinear Coupled Kirchhoff-Type Equations 被引量:3
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作者 Guoguang Lin Ming Zhang 《Advances in Pure Mathematics》 2018年第1期1-10,共10页
This paper deals with the Hausdorff dimensions of the global attractor for a class of Kirchhoff-type coupled equations with strong damping and source terms. We obtain a precise estimate of upper bound of Hausdorff dim... This paper deals with the Hausdorff dimensions of the global attractor for a class of Kirchhoff-type coupled equations with strong damping and source terms. We obtain a precise estimate of upper bound of Hausdorff dimension of the global attractor. 展开更多
关键词 Kirchhoff-Type EQUATIONS The global Attractor HAUSDORFF dimension
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THE GLOBAL AND LOCAL C^(2)-SOLUTIONS FOR THE WAVE EQUATION □u = G(u_t, Du) IN THREE SPACE DIMENSIONS 被引量:2
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作者 赖绍永 《Acta Mathematica Scientia》 SCIE CSCD 2000年第4期495-503,共9页
Kunio Hidano[4] has shown that the global and local C2-solutions for semilinear wave equations with spherical symmetry in three space dimensions. This paper studies the global and local C2-solutions for the semilinea... Kunio Hidano[4] has shown that the global and local C2-solutions for semilinear wave equations with spherical symmetry in three space dimensions. This paper studies the global and local C2-solutions for the semilinear wave equations without spherical symmetry in three space dimensions. A problem put forward by Hiroyuki Takamura[2] is partially answered. 展开更多
关键词 Semilinear wave equations global and local C^(2)-solutions three space dimensions
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Global Attractor and Dimension Estimation for a 2D Generalized Anisotropy Kuramoto-Sivashinsky Equation 被引量:3
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作者 Meixia Wang Cuicui Tian Guoguang Lin 《International Journal of Modern Nonlinear Theory and Application》 2014年第4期163-172,共10页
In this paper, firstly, some priori estimates are obtained for the existence and uniqueness of solutions of a two dimensional generalized anisotropy Kuramoto-Sivashinsky Equation. Then we prove the existence of the gl... In this paper, firstly, some priori estimates are obtained for the existence and uniqueness of solutions of a two dimensional generalized anisotropy Kuramoto-Sivashinsky Equation. Then we prove the existence of the global attractor. Finally, we get the upper bound estimation of the Haus-dorff and fractal dimension of attractor. 展开更多
关键词 Kuramoto-Sivashinsky Equation EXISTENCE global ATTRACTOR dimension Estimation
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Global Attractors and Their Dimension Estimates for a Class of Generalized Kirchhoff Equations 被引量:3
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作者 Guoguang Lin Lujiao Yang 《Advances in Pure Mathematics》 2021年第4期317-333,共17页
In this paper, we studied the long-time properties of solutions of generalized Kirchhoff-type equation with strongly damped terms. Firstly, appropriate assumptions are made for the nonlinear source term <span style... In this paper, we studied the long-time properties of solutions of generalized Kirchhoff-type equation with strongly damped terms. Firstly, appropriate assumptions are made for the nonlinear source term <span style="white-space:nowrap;"><em>g</em> (<em>u</em>)</span> and Kirchhoff stress term <span style="white-space:nowrap;"><em>M</em> (<em>s</em>)</span> in the equation, and the existence and uniqueness of the solution are proved by using uniform prior estimates of time and Galerkin’s finite element method. Then, abounded absorption set <em>B</em><sub>0<em>k</em></sub> is obtained by prior estimation, and the Rellich-kondrachov’s compact embedding theorem is used to prove that the solution semigroup <span style="white-space:nowrap;"><em>S</em> (<em>t</em>)</span> generated by the equation has a family of the global attractor <span style="white-space:nowrap;"><em>A</em><sub><em>k</em></sub></span> in the phase space <img src="Edit_250265b5-40f0-4b6c-b669-958eb1938010.png" width="120" height="20" alt="" />. Finally, linearize the equation and verify that the semigroups are Frechet diifferentiable on <em>E<sub>k</sub></em>. Then, the upper boundary estimation of the Hausdorff dimension and Fractal dimension of a family of the global attractor <em>A<sub>k</sub></em> was obtained. 展开更多
关键词 Generalized Kirchhoff Equation The Existence and Uniqueness of Solution A Family of the global Attractor dimension Estimation
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Global Attractors and Dimension Estimation of the 2D Generalized MHD System with Extra Force 被引量:1
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作者 Zhaoqin Yuan Liang Guo Guoguang Lin 《Applied Mathematics》 2015年第4期724-736,共13页
In this paper, firstly, some priori estimates are obtained for the existence and uniqueness of solu-tions of a two dimensional generalized magnetohydrodynamic (MHD) system. Then the existence of the global attractor i... In this paper, firstly, some priori estimates are obtained for the existence and uniqueness of solu-tions of a two dimensional generalized magnetohydrodynamic (MHD) system. Then the existence of the global attractor is proved. Finally, the upper bound estimation of the Hausdorff and fractal dimension of attractor is got. 展开更多
关键词 MHD SYSTEM EXISTENCE global ATTRACTOR dimension Estimation
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The Global Attractors and Their Hausdorff and Fractal Dimensions Estimation for the Higher-Order Nonlinear Kirchhoff-Type Equation with Strong Linear Damping 被引量:11
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作者 Yunlong Gao Yuting Sun Guoguang Lin 《International Journal of Modern Nonlinear Theory and Application》 2016年第4期185-202,共18页
In this paper, we study the longtime behavior of solution to the initial boundary value problem for a class of strongly damped Higher-order Kirchhoff type equations: . At first, we prove the existence and uniqueness o... In this paper, we study the longtime behavior of solution to the initial boundary value problem for a class of strongly damped Higher-order Kirchhoff type equations: . At first, we prove the existence and uniqueness of the solution by priori estimation and the Galerkin method. Then, we obtain to the existence of the global attractor. At last, we consider that the estimation of the upper bounds of Hausdorff and fractal dimensions for the global attractors are obtained. 展开更多
关键词 Nonlinear Higher-Order Kirchhoff Type Equation The Existence and Uniqueness The global Attractors Hausdorff dimensions Fractal dimensions
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Global Attractor of Two-Dimensional Strong Damping KDV Equation and Its Dimension Estimation
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作者 Cheng Zhang Guoguang Lin 《Applied Mathematics》 2014年第1期7-15,共9页
Firstly, a priori estimates are obtained for the existence and uniqueness of solutions of two dimensional KDV equations, and prove the existence of the global attractor, finally get the upper bound estimation of the H... Firstly, a priori estimates are obtained for the existence and uniqueness of solutions of two dimensional KDV equations, and prove the existence of the global attractor, finally get the upper bound estimation of the Hausdorff and fractal dimension of attractors. 展开更多
关键词 KDV Equation STRONGLY DAMPED Existence global ATTRACTOR dimension Estimation
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GLOBAL WELL-POSEDNESS IN ENERGY SPACE OF SMALL AMPLITUDE SOLUTIONS FOR KLEIN-GORDON-ZAKHAROV EQUATION IN THREE SPACE DIMENSION
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作者 霍朝辉 《Acta Mathematica Scientia》 SCIE CSCD 2016年第4期1117-1152,共36页
The Cauchy problem of the Klein-Gordon-Zakharov equation in three dimensional space is considered. It is shown that it is globally well-posed in energy space H^1 × L^2 × L^2 ×... The Cauchy problem of the Klein-Gordon-Zakharov equation in three dimensional space is considered. It is shown that it is globally well-posed in energy space H^1 × L^2 × L^2 × H^-1 if small initial data (u0 (x), u1 (x), n0 (x), n1 (x)) ∈ (H^1 ×L^2× L^2 × H^-1). It answers an open problem: Is it globally well-posed in energy space H^1 × L^2 × L^2 × H^-1 for 3D Klein-Gordon- Zakharov equation with small initial data [1, 2]? The method in this article combines the linear property of the equation ( dispersive property) with nonlinear property of the equation (energy inequalities). We mainly extend the spaces F^s and N^3 in one dimension [3] to higher dimension. 展开更多
关键词 global well-posedness 3D Klein-Gordon-Zakharov equation dyadic Xs b spacesin higher dimension
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Global Pressure of One-Dimensional Polydisperse Granular Gases Driven by Gaussian White Noise
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作者 CHEN Zhi-Yuan ZHANG Duan-Ming +4 位作者 YANG Feng-Xia HUANG Ming-Tao LI Rui ZHANG Ling ZHU Hong-Ying 《Communications in Theoretical Physics》 SCIE CAS CSCD 2007年第3X期481-486,共6页
We study the global pressure of a one-dimensional polydisperse granular gases system for the first time, in which the size distribution of particles has the fractal characteristic and the inhomogeneity is described by... We study the global pressure of a one-dimensional polydisperse granular gases system for the first time, in which the size distribution of particles has the fractal characteristic and the inhomogeneity is described by a fractal dimension D. The particles are driven by Gaussian white noise and subject to inelastic mutual collisions. We define the global pressure P of the system as the impulse transferred across a surface in a unit of time, which has two contributions, one from the translational motion of particles and the other from the collisions. Explicit expression for the global pressure in the steady state is derived. By molecular dynamics simulations, we investigate how the inelasticity of collisions and the inhomogeneity of the particles influence the global pressure. The simulation results indicate that the restitution coefficient e and the fractal dimension D have significant effect on the pressure. 展开更多
关键词 global pressure restitution coefficient e fractal dimension D Gaussian white noise polydisperse granular gases
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The Global Attractors and Dimensions Estimation for the Higher-Order Nonlinear Kirchhoff-Type Equation with Strong Damping
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作者 Guoguang Lin Yalan Yang 《International Journal of Modern Nonlinear Theory and Application》 2020年第4期63-80,共18页
The initial boundary value problems for a class of high order Kirchhoff type equations with nonlinear strongly damped terms are considered. We establish the existence and uniqueness of the global solution of the probl... The initial boundary value problems for a class of high order Kirchhoff type equations with nonlinear strongly damped terms are considered. We establish the existence and uniqueness of the global solution of the problem by using prior estimates and Galerkin’s method under proper assumptions for the rigid term. Then the compact method is used to prove the existence of a compact family of global attractors in the solution semigroup generated by the problem. Finally, the Frechet differentiability of the operator semigroup and the decay of the volume element of linearization problem are proved, and the Hausdorff dimension and Fractal dimension of the family of global attractors are obtained. 展开更多
关键词 Nonlinear Higher-Order Kirchhoff Type Equation The Priori Estimates The Galerkin’s Method The global Attractors dimension Estimation
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A Family of Global Attractors for the Generalized Kirchhoff-Beam Equations
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作者 Guoguang Lin Boshi Chen 《Journal of Applied Mathematics and Physics》 2023年第7期1945-1963,共19页
In this paper, we discuss the existence and uniqueness of global solutions, the existence of the family of global attractors and its dimension estimation for generalized Beam-Kirchhoff equation under initial condition... In this paper, we discuss the existence and uniqueness of global solutions, the existence of the family of global attractors and its dimension estimation for generalized Beam-Kirchhoff equation under initial conditions and boundary conditions, using the previous research results for reference. Firstly, the existence of bounded absorption set is proved by using a prior estimation, then the existence and uniqueness of the global solution of the problem is proved by using the classical Galerkin’s method. Finally, Housdorff dimension and fractal dimension of the family of global attractors are estimated by linear variational method and generalized Sobolev-Lieb-Thirring inequality. 展开更多
关键词 Beam-Kirchhoff Equation Galerkin’s Method Family of global Attractors Housdorff dimension Fractal dimension
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基于墙角族语义尺寸链的绑架定位研究
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作者 蒋林 李云飞 +3 位作者 雷斌 汤勃 刘奇 郭宇飞 《电子学报》 EI CAS CSCD 北大核心 2024年第7期2356-2368,共13页
针对目前原始自适应蒙特卡洛定位(Adaptive Monte Carlo Localization,AMCL)在相似环境下绑架检测容易出错且重定位极易失败等问题,提出基于墙角族语义尺寸链的改进AMCL算法.融合机器人多传感器信息和Gmapping算法构建二维栅格地图,基于... 针对目前原始自适应蒙特卡洛定位(Adaptive Monte Carlo Localization,AMCL)在相似环境下绑架检测容易出错且重定位极易失败等问题,提出基于墙角族语义尺寸链的改进AMCL算法.融合机器人多传感器信息和Gmapping算法构建二维栅格地图,基于Yolov5获取室内环境的目标检测框和类别信息,结合GrabCut算法和贝叶斯方法构建增量式语义映射地图;通过墙角的凸、凹和墙角相对于机器人的方位角对墙角进行分类,充分发掘语义映射地图中各墙角之间、墙角与室内物体之间的类别和位置关系,构建墙角族语义尺寸链和相应检索表;在定位过程中,基于墙角族语义尺寸链进行全局预定位,提出绑架检测机制进行绑架检测,在检测到绑架事件发生后,基于改进AMCL算法实现定位自恢复.最后,通过真实环境下的绑架实验验证了本文方法的有效性,实验表明,所提方法的全局定位准确率、全局定位速率、绑架检测准确率和绑架后定位准确率在相似环境下分别提升了42%、214%、88%和72%;在非相似环境下分别提升了44%、152%、12%和92%;在长走廊环境下分别提升了36%、426%、26%和68%. 展开更多
关键词 绑架检测 墙角族语义尺寸链 贝叶斯方法 全局预定位 定位自恢复
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教育强国建设背景下的高等教育国际化:关键维度、国际方位与发展路径
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作者 刘宝存 庞若洋 《云南师范大学学报(哲学社会科学版)》 北大核心 2024年第5期92-103,共12页
国际化作为推动高等教育资源在各国间及国家内部配置的重要举措,是打造支撑国家发展的高质量高等教育体系和提升高等教育对外传播能力及国际影响力的根本路径,也是高等教育强国建设的题中之义。基于简·奈特对于教育国际化的概念界... 国际化作为推动高等教育资源在各国间及国家内部配置的重要举措,是打造支撑国家发展的高质量高等教育体系和提升高等教育对外传播能力及国际影响力的根本路径,也是高等教育强国建设的题中之义。基于简·奈特对于教育国际化的概念界定,研究从制度国际化、办学国际化、人员国际化、科研国际化和课程国际化5个维度对各国高等教育国际化发展水平进行比较,发现中国高等教育国际化正由内向型发展模式向外向型发展模式转型,在全球位于中上游水平。与此同时,我国在来华留学生规模、外籍师资规模、在外开设海外分校力度、英文授课项目的规模与结构等方面依旧存在短板。立足教育强国建设,未来我国应加强政府引导,优化高等教育国际化制度建设与格局规划;持续提升高等教育吸引力,服务人才中心与创新高地建设;推动在地国际化发展,加强本土高校国际化人才培养能力;坚持“走出去”与“引进来”相结合,进一步扩大中国高等教育的全球影响力。 展开更多
关键词 高等教育强国 高等教育国际化 关键维度 发展路径 外向型发展
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全球人工智能治理:多元化进程与竞争性图景
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作者 封帅 薛世锟 马依若 《战略决策研究》 2024年第3期87-108,112,共23页
人工智能技术的快速发展对国际体系产生了重要影响。国家维度可以成为分析和展示当前全球人工智能治理进程的重要视角。从国家维度展开全球人工智能治理全景图,将会呈现出以三条核心路径为基本架构的多元化进程,分别是美国作为唯一代表... 人工智能技术的快速发展对国际体系产生了重要影响。国家维度可以成为分析和展示当前全球人工智能治理进程的重要视角。从国家维度展开全球人工智能治理全景图,将会呈现出以三条核心路径为基本架构的多元化进程,分别是美国作为唯一代表的权力目标导向路径,以维护智能领域的霸权为基本特征;以欧盟等为代表的安全导向路径,其突出特征是监管优先;以中日等国为代表的发展导向路径,将治理工具与发展战略结合,希望实现技术和产业的赶超。在无政府状态的制约下,多元化与竞争性将成为国家维度下全球人工智能治理的主要特征。 展开更多
关键词 人工智能治理 全球图景 国家维度 多元化进程 竞争性图景
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跨境数据流动政策偏好的全球分布:国家维度的治理模式比较研究
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作者 封帅 薛世锟 《俄罗斯学刊》 2024年第3期5-28,共24页
数据跨境流动是数字经济发展的基础,但也蕴含着很多风险与挑战。目前,世界各国在数据跨境流动领域已经形成了多种治理模式。美国为维护其数字霸权,全力推动数据“自由化”主张,日欧等发达经济体则选择推动有限的自由化与严格数据保护。... 数据跨境流动是数字经济发展的基础,但也蕴含着很多风险与挑战。目前,世界各国在数据跨境流动领域已经形成了多种治理模式。美国为维护其数字霸权,全力推动数据“自由化”主张,日欧等发达经济体则选择推动有限的自由化与严格数据保护。很多发展中国家要求数据本地化以推动本国数字经济发展。俄罗斯具有更多的危机意识,从安全底线思维出发,推进严格的本地化与安全化数据治理模式。中国则以中国式现代化为导向,以更为灵活和敏捷的思路开展数据治理,保持发展目标与安全目标的动态平衡。以各国在跨境数据治理中的主观意愿与客观结果作标准,可以构建一个针对跨境数据流动政策的二维分析展示框架。通过对该框架的分析,能够较为清晰地展示各国跨境数据政策的偏好、特征及互动方式,勾勒出跨境数据流动政策领域以“多模式交织碰撞”为主要特征的全球图景。 展开更多
关键词 跨境数据流动 政策偏好 国家维度 治理模式 全球图景
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基于势场增强烟花算法的二维全局路径规划
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作者 孙鹏耀 黄炎焱 王凯生 《兵工学报》 EI CAS CSCD 北大核心 2024年第10期3499-3518,共20页
高质量路径是未来无人自主作战的重要前提,针对复杂障碍环境下路径规划问题,提出基于势场增强烟花算法(Potential-field Enhanced Fireworks Algorithm,PEFWA)的路径规划方法。建立规划空间模型与动态维数路径描述模型,设立包含可行性... 高质量路径是未来无人自主作战的重要前提,针对复杂障碍环境下路径规划问题,提出基于势场增强烟花算法(Potential-field Enhanced Fireworks Algorithm,PEFWA)的路径规划方法。建立规划空间模型与动态维数路径描述模型,设立包含可行性因素与长度因素的目标函数,将路径规划问题转化为最优化问题;设计动态维数烟花初始化与维度增删操作,使相邻维度个体满足距离约束;提出基于障碍空间信息的爆炸幅度计算方法和连续维度选择方法,生成改进爆炸火花,提高全局搜索能力;引入势场引导策略,生成势场增强爆炸火花,让所选维度在合力方向上多次搜索,提高局部优化能力;采用交叉组合策略生成变异火花,并对超出规划空间的维度个体进行删减操作,提高多样性烟花高效产生能力;提出基于余弦相似度的双层锦标赛选择策略,提高烟花特征延续能力。采用相同基准函数,将PEFWA与烟花算法(Fireworks Algorithm,FWA)、粒子群优化(Particle Swarm Optimization,PSO)算法、遗传算法(Genetic Algorithm,GA)进行对比。研究结果表明:PEFWA的优化性能更强;在相同复杂障碍环境下进行多次路径规划仿真实验,验证了PEFWA中各个模块的有效性,与PSO算法、GA、A*算法相比,PEFWA在规划成功率、路径长度、路径光滑度、结果鲁棒性等方面均有优势;PEFWA在二维全局路径规划问题上具有有效性与优越性。 展开更多
关键词 全局路径规划 烟花算法 势函数 动态维数 交叉组合
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Homological dimensions of gentle algebras via geometric models
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作者 Yu-Zhe Liu Hanpeng Gao Zhaoyong Huang 《Science China Mathematics》 SCIE CSCD 2024年第4期733-766,共34页
Let A=kQ/I be a finite-dimensional basic algebra over an algebraically closed field k,which is a gentle algebra with the marked ribbon surface(SA,MA,ΓA).It is known that SAcan be divided into some elementary polygons... Let A=kQ/I be a finite-dimensional basic algebra over an algebraically closed field k,which is a gentle algebra with the marked ribbon surface(SA,MA,ΓA).It is known that SAcan be divided into some elementary polygons{Δi|1≤i≤d}byΓA,which has exactly one side in the boundary of SA.Let■(Δi)be the number of sides ofΔibelonging toΓAif the unmarked boundary component of SAis not a side ofΔi;otherwise,■(Δi)=∞,and let f-Δbe the set of all the non-co-elementary polygons and FA(resp.f-FA)be the set of all the forbidden threads(resp.of finite length).Then we have(1)the global dimension of A is max1≤i≤d■(Δi)-1=maxΠ∈FAl(Π),where l(Π)is the length ofΠ;(2)the left and right self-injective dimensions of A are 0,if Q is either a point or an oriented cycle with full relations.masΔi∈f-Δ{1,■(Δi)-1}=max n∈f-F_(A)l(П),otherwise,As a consequence,we get that the finiteness of the global dimension of gentle algebras is invariant under AvellaGeiss(AG)-equivalence.In addition,we get that the number of indecomposable non-projective Gorenstein projective modules over gentle algebras is also invariant under AG-equivalence. 展开更多
关键词 global dimension self-injective dimension gentle algebras marked ribbon surfaces geometric models AG-equivalence
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习近平文化思想的四维向度
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作者 董庆强 张雪怡 《沂蒙干部学院学报》 2024年第3期43-50,共8页
习近平文化思想是以习近平同志为核心的党中央对新时代党领导文化建设实践经验的理论总结,深化了对文化建设规律和人类文明发展规律的认识。习近平文化思想回应人民之呼,满足人民精神需要,促进人的全面发展;回应国家之要,为建设文化强... 习近平文化思想是以习近平同志为核心的党中央对新时代党领导文化建设实践经验的理论总结,深化了对文化建设规律和人类文明发展规律的认识。习近平文化思想回应人民之呼,满足人民精神需要,促进人的全面发展;回应国家之要,为建设文化强国和推进中国式现代化提供文化支撑和思想指引;回应政党之责,坚持党对文化工作领导权,担负新的文化使命;回应世界之需,推动不同文明交流互鉴,引领人类文明发展方向。反映了当今中国对文化建设和人类文明发展规律、发展样式和发展方向的总体看法,展现了中华民族和中国共产党观察世界的文化视角。 展开更多
关键词 习近平文化思想 价值向度 现实向度 主体向度 世界向度
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