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Optimal investment, retirement, and life insurance with consumption ratcheting and time-inhomogeneous utility

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Science China Mathematics 2025年

作者： Jie Xing Jingtang Ma School of Big Data Application and economics Guizhou University of Finance and Economics School of Mathematics Southwestern University of Finance and Economics

In this paper, we study a portfolio selection problem of an investor with a retirement option, who has possibility to buy life insurance and does not tolerate any decline in consumption. The agent's optimization problem can be viewed as a mixed singular control and optimal stopping problem with time-inhomogeneous utility functions. The closed-form optimal solution is not available in general. We use the dual control method to convert the original problem into two classes of optimal stopping problems in finite and infinite *** show that the optimal consumption strategy and the best retirement time depend on the free-boundary functions which satisfy Fredholm and Volterra integral equations. We derive the closed-form formulas for these two free boundaries for some special cases and develop numerical methods to solve the integral equations of the free boundaries for general cases.

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How Does the Belt and Road Initiative Improve China's Product Export Potential:A Global Value Chain Perspective

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China & World Economy 2025年第1期33卷 195-222页

作者： Liang Zhang Dahai Fu Chengjun Wu Yuanyuan Liu Yanle Xi School of economics Zhongnan University of Economics and LawChina School of International Trade and economics Central University of Finance and EconomicsChina School of International Business Southwestern University of Finance and EconomicsChina School of Business Administration Zhongnan University of Economics and LawChina

This study examines the impact of the Belt and Road Initiative(BRI)on China's export potential at the product *** country–product-level data from the Centre d'Etudes Prospectives d'Informations Internationales-Base pour l'Analyse du Commerce International(CEPII-BACI),which includes 5,049 product types across 196 economies from 2007 to 2022,it explores the trade effects of the BRI and its mechanisms from the perspective of global value *** results indicate that the BRI has increased China's product export potential significantly to participating *** BRI has had the greatest impact on capital goods and labor-and capital-intensive *** effect has been most pronounced in China's exports to Southeast Asia,South Asia,and *** mechanism analysis reveals that the BRI has improved the division of labor in the global value chains for participating countries along the BRI,strengthened China's position in their output supply chains,and stimulated the growth of China's exports.

关键词： the Belt and Road Initiative difference-in-differences export potential global value chains

Predictor-based sampled-data output-feedback control for feedforward nonlinear time-delay systems

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Control Theory and Technology 2025年第1期23卷 105-117页

作者： Wenjie Zhang Weihao Pan Xianfu Zhang Qingrong Liu School of Control Science and Engineering Shandong UniversityJinan250061ShandongChina School of Mathematics and Quantitative economics Shandong University of Finance and EconomicsJinan250014ShandongChina

This paper studies global stabilization via predictor-based sampled-data output feedback for a class of feedforward nonlinear time-delay *** that the traditional sampled-data observer via zero-order holder may result in the performance degradation of the *** this paper,an improved predictor-based observer is designed to compensate for the influence of the unmeasurable states,sampling errors and output *** addition,a sampled-data output-feedback controller is also constructed using the gain scaling *** the Lyapunov-Krasovskii functional method,the global exponential stability of the resulting closed-loop system can be guaranteed under some sufficient *** simulation results are provided to demonstrate the main results.

关键词： Feedforward nonlinear systems Time delay Predictor-based observer Sampled-data output-feedback controller

Darboux transformation,positon solution,and breather solution of the third-order flow Gerdjikov–Ivanov equation

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Chinese Physics B 2025年第1期34卷 195-202页

作者： Shuzhi Liu Ning-Yi Li Xiaona Dong Maohua Li School of Statistics and Data Science Ningbo University of TechnologyNingbo 315211China School of Mathematics and Statistics Ningbo UniversityNingbo 315211China college of Wealth and Management Ningbo University of Finance and EconomicsNingbo 315175China

The third-order flow Gerdjikov–Ivanov(TOFGI)equation is studied,and the Darboux transformation(DT)is used to obtain the determinant expression of the solution of this *** this basis,the soliton solution,rational solution,positon solution,and breather solution of the TOFGI equation are obtained by taking zero seed solution and non-zero seed *** exact solutions and dynamic properties of the Gerdjikov–Ivanov(GI)equation and the TOFGI equation are compared in detail under the same conditions,and it is found that there are some differences in the velocities and trajectories of the solutions of the two equations.

关键词： third-order flow Gerdjikov-Ivanov equation solitons positons breathers

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The Spillover Effects of International Co-production in the Chinese Film Industry

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China & World Economy 2025年第1期33卷 101-131页

作者： Feng Yu Ning Li Jing Yan Yan Zhang School of economics and Management University of Science and Technology BeijingChina School of International Trade and economics Central University of Finance and EconomicsChina

This study examines the spillover effects of international film co-production using data on films released in the Chinese mainland from 2006 to *** results indicate that local film producers can enhance their product performance by leveraging the expertise and practices of more sophisticated foreign firms during international *** effects were observed related to budget size,firm size,ownership structure,and cultural *** spillover effects can occur through two mechanisms:the demonstration effect(the adoption of more advanced technology)and the labor mobility effect(actors or directors upgrading their skills).An instrumental variable approach is employed to address endogeneity *** study contributes to the spillover effects of international co-production,which has been neglected in the *** empirical findings suggest that engaging in international co-production can potentially boost productivity for firms from developing *** country governments may consider offering preferential policies to promote international co-production as an alternative to foreign direct investment(FDI),thereby fostering positive spillover effects.

关键词： demonstration effect international co-production labor mobility effect film industry spillovereffects

On Modified Rota-Baxter Hom-Lie Algebras

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Journal of Mathematical Research with Applications 2025年第2期 163-178页

作者： Wen TENG School of Mathematics and Statistics Guizhou University of Finance and Economics

Semenov-Tian-Shansky has given the solution of the modified classical Yang-Baxter equation, which was called the modified r-matrix. Relevant studies have been extensive in recent times. In this paper, we introduce the concept and representations of modified RotaBaxter Hom-Lie algebras. We develop a cohomology of modified Rota-Baxter Hom-Lie algebras with coefficients in a suitable representation. As applications, we study formal deformations and abelian extensions of modified Rota-Baxter Hom-Lie algebras in terms of second cohomology groups.

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Extensions and Deformations of 3-Lie Algebras with Higher Derivations

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Journal of Mathematical Research with Applications 2025年第1期45卷 20-32页

作者： Shuangjian GUO School of Mathematics and Statistics Guizhou University of Finance and Economics

In this paper, we call a tuple consisting of 3-Lie algebra and a higher derivation on it a 3-LieHDer pair. We introduce a cohomology theory of 3-LieHDer pairs. Next, we interpret the second cohomology group as the space of all isomorphism classes of abelian extensions. Finally,we consider formal deformations of 3-LieHDer pairs that are governed by the cohomology with self-coefficient.

关键词： higher derivations 3-LieHDer pairs cohomology extensions formal deformations

Spatial Evolution Characteristics and Influencing Factors of Urban Green Innovation in China

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Chinese Geographical Science 2025年第2期 234-249页

作者： PENG Wenbin SU Xinyi TANG Yueliang School of Economic Geography Hunan University of Finance and Economics (Hunan Institute of Economic Geography) School of Urban and Regional Science Shanghai University of Finance and Economics

Cities are important carriers of green innovation. The foundation for accelerating China's ecological civilization construction and fostering regionally coordinated and sustainable development is quantitative analysis of the spatial evolution pattern and influencing factors of urban green innovation, as well as revealing the development differences between regions. This study's research object includes 284 Chinese cities that are at the prefecture level or above, excluding Xizang, Hong Kong, Macao, and Taiwan of China due to incomplete data. The spatial evolution characteristics of urban green innovation in China between 2005 and 2021 are comprehensively described using the gravity center model and boxplot analysis. The factors that affect urban green innovation are examined using the spatial Durbin model(SDM). The findings indicate that: 1) over the period of the study, the gravity center of urban green innovation in China has always been distributed in the Henan-Anhui border region, showing a migration characteristic of ‘initially shifting northeast,subsequently southeast', and the migration speed has gradually increased. 2) Although there are also noticeable disparities in east-west,the north-south gap is the main cause of the shift in China's urban green innovation gravity center. The primary areas of urban green innovation in China are the cities with green innovation levels higher than the median. 3) The main influencing factor of urban green innovation is the industrial structure level. The effect of the financial development level, the government intervention level, and the openness to the outside world degree on urban green innovation is weakened in turn. The environmental regulation degree is not truly influencing urban green innovation. The impact of various factors on green innovation across cities of different sizes, exhibiting heterogeneity. This study is conducive to broadening the academic community's comprehension of the spatial evolution characteri

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On Bowen Entropy for Stable Sets in Positive Entropy Systems

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数学进展 2025年第1期54卷 99-112页

作者： ZHANG Zhengwei YAN Kesong ZENG Fanping college of Mathematics and Information Science Guangxi UniversityNanningGuangxi530004P.R.China School of Mathematics and Quantitative economics Guangxi University of Finance and EconomicsNanningGuangxi530003P.R.China Guangxi Key Laboratory of Quantitative economics Guangxi University of Finance and EconomicsNanningGuangxi530003P.R.China

In this paper,we study the Bowen entropy of stable sets in positive entropy G-system of amenable group *** lower bound of the Bowen entropy of these sets are estimated.

关键词： positive entropy stable set Bowen entropy amenable group action