数学最新文献_第4页

Quantifying the likelihood of learning collusive strategy equilibria. 量化学习串通策略均衡的可能性。

IF 3.2 2区数学

Chaos Pub Date : 2025-08-01 DOI: 10.1063/5.0281443

Janusz M Meylahn

引用次数: 0

Dynamical analysis and solutions of coupled 4D fractional differential systems with applications to predictability limit quantification in ocean-atmosphere models. 耦合四维分数微分系统的动力学分析和解及其在海洋-大气模式可预测性极限量化中的应用。

IF 3.2 2区数学

Chaos Pub Date : 2025-08-01 DOI: 10.1063/5.0283492

Xiaoyu Chen, Hongtao Fan, Yajing Li

{"title":"Dynamical analysis and solutions of coupled 4D fractional differential systems with applications to predictability limit quantification in ocean-atmosphere models.","authors":"Xiaoyu Chen, Hongtao Fan, Yajing Li","doi":"10.1063/5.0283492","DOIUrl":"https://doi.org/10.1063/5.0283492","url":null,"abstract":"For coupled two-dimensional fractional differential systems, a new two-step fractional-order Runge-Kutta method is proposed in this paper, which can reach a convergence order of 2α, with α being the fractional-order number. Further, we extend the two-step fractional-order Runge-Kutta algorithm to any coupled n-dimensional fractional differential system while maintaining convergence and consistency. To demonstrate the validity of the proposed method, numerical experiments are given for a four-dimensional fractional Lorenz system, and the dynamics of the four-dimensional fractional Lorenz system is analyzed using Lyapunov characteristic exponents, bifurcation diagrams, chaos diagrams, and C0 complexity. The results demonstrate that the system exhibits a diverse dynamical behavior and a broader range of fractional orders [0.43, 1] is accessible to the periodic orbit at the same parameter, compared to previous findings [He et al., Math. Methods Appl. Sci. 39, 2965-2973 (2016)]. Finally, we use global attractor radius and attractor radius to investigate the predictability of the coupled fractional-order ocean-atmosphere system [Li et al., Clim. Dyn. 51, 2359-2374 (2018)]. The results show that both global attractor radius and attractor radius decrease with decreasing fractional order, and the smaller the initial perturbation, the longer it takes to reach the attractor radius, but the attractor radius to the global attractor radius is not significantly correlated with the initial perturbation. These findings suggest that the predictability of the coupled fractional ocean-atmosphere system is limited by the presence of long-range memory effects captured in the fractional-order differential equations. By offering quantitative assessments of predictability, these approaches enhance our understanding of the intricate dynamics within such systems and can support informed decision-making in addressing and mitigating the effects of climate change on the global atmosphere and oceans.","PeriodicalId":9974,"journal":{"name":"Chaos","volume":"35 8","pages":""},"PeriodicalIF":3.2,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144764641","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Dynamic analysis of a generalized attention deficit disorder model with Soboleva activation functions. 具有Soboleva激活函数的广义注意缺陷障碍模型的动态分析。

IF 3.2 2区数学

Chaos Pub Date : 2025-08-01 DOI: 10.1063/5.0280557

L Moysis, M Lawnik, K F Kollias, M S Baptista, S Goudos, G Fragulis

引用次数: 0

Recurrence condensation during critical transitions in complex systems. 复杂系统临界跃迁过程中的重复凝聚。

IF 3.2 2区数学

Chaos Pub Date : 2025-08-01 DOI: 10.1063/5.0267157

Manaswini Jella, Induja Pavithran, Vishnu R Unni, Norbert Marwan, Jürgen Kurths, R I Sujith

{"title":"Recurrence condensation during critical transitions in complex systems.","authors":"Manaswini Jella, Induja Pavithran, Vishnu R Unni, Norbert Marwan, Jürgen Kurths, R I Sujith","doi":"10.1063/5.0267157","DOIUrl":"https://doi.org/10.1063/5.0267157","url":null,"abstract":"Critical transitions in complex systems pose challenges for the healthy functioning of natural and engineered systems, sometimes with catastrophic outcomes. These critical points, where small changes cause large regime shifts, are difficult to detect-especially in noisy, high-dimensional settings. We investigate such a transition from chaotic to periodic oscillations via intermittency in a turbulent fluid mechanical system by using recurrence analysis. Recurrence plots (RPs) constructed from the time series of a state variable reveal a distinct progression from disordered, short broken diagonal lines to patches of ordered short diagonal lines and, ultimately, to a pattern of long continuous diagonal lines. This evolution in the recurrence patterns captures a transition from dynamics involving multiple time scales to a dominant single time scale; we term this phenomenon \"recurrence condensation.\" We quantify recurrence condensation using recurrence quantification measures, such as the recurrence time, determinism, entropy, laminarity, and trapping time, all of which show collapse to a single dominant time scale. Furthermore, these recurrence measures exhibit power-law scaling with the deviation of the control parameter from the critical point. Optimizing for the best power law reveals the critical value of the parameter. We apply this method to the synthetic data from a basic noisy Hopf bifurcation model and confirm that the detected critical point coincides with the bifurcation point. Our findings offer insights into identifying the critical points in noisy systems with gradual transitions, where the transition point is not well defined.","PeriodicalId":9974,"journal":{"name":"Chaos","volume":"35 8","pages":""},"PeriodicalIF":3.2,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144764644","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Approximate packing of independent transversals in locally sparse graphs 局部稀疏图中独立截线的近似填充

IF 1.2 1区数学

Journal of Combinatorial Theory Series B Pub Date : 2025-07-31 DOI: 10.1016/j.jctb.2025.07.005

Debsoumya Chakraborti , Tuan Tran

{"title":"Approximate packing of independent transversals in locally sparse graphs","authors":"Debsoumya Chakraborti , Tuan Tran","doi":"10.1016/j.jctb.2025.07.005","DOIUrl":"10.1016/j.jctb.2025.07.005","url":null,"abstract":"<div><div>Fix <math><mi>ε</mi><mo>></mo><mn>0</mn></math> and consider a multipartite graph G with maximum degree at most <math><mo>(</mo><mn>1</mn><mo>−</mo><mi>ε</mi><mo>)</mo><mi>n</mi></math>, parts <math><msub><mrow><mi>V</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>,</mo><mo>…</mo><mo>,</mo><msub><mrow><mi>V</mi></mrow><mrow><mi>k</mi></mrow></msub></math> of the same size n, and where every vertex has at most <math><mi>o</mi><mo>(</mo><mi>n</mi><mo>)</mo></math> neighbors in any part <math><msub><mrow><mi>V</mi></mrow><mrow><mi>i</mi></mrow></msub></math>. Loh and Sudakov proved that any such G has an independent transversal. They further conjectured that the vertex set of G can be decomposed into pairwise disjoint independent transversals. In the present paper, we resolve this conjecture approximately by showing that G contains <math><mo>(</mo><mn>1</mn><mo>−</mo><mi>ε</mi><mo>)</mo><mi>n</mi></math> pairwise disjoint independent transversals. As applications, we give approximate answers to questions of Yuster, and of Fischer, Kühn, and Osthus.</div></div>","PeriodicalId":54865,"journal":{"name":"Journal of Combinatorial Theory Series B","volume":"175 ","pages":"Pages 187-212"},"PeriodicalIF":1.2,"publicationDate":"2025-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144738353","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

An L ∞ $L_infty$ structure for Legendrian contact homology Legendrian接触同调的L∞$L_infty$结构

IF 1.1 2区数学

Journal of Topology Pub Date : 2025-07-31 DOI: 10.1112/topo.70034

Lenhard Ng

{"title":"An \u0000 \u0000 \u0000 L\u0000 ∞\u0000 \u0000 $L_infty$\u0000 structure for Legendrian contact homology","authors":"Lenhard Ng","doi":"10.1112/topo.70034","DOIUrl":"https://doi.org/10.1112/topo.70034","url":null,"abstract":"For any Legendrian knot or link in <math>\u0000 <semantics>\u0000 <msup>\u0000 <mi>R</mi>\u0000 <mn>3</mn>\u0000 </msup>\u0000 <annotation>$mathbb {R}^3$</annotation>\u0000 </semantics></math>, we construct an <math>\u0000 <semantics>\u0000 <msub>\u0000 <mi>L</mi>\u0000 <mi>∞</mi>\u0000 </msub>\u0000 <annotation>$L_infty$</annotation>\u0000 </semantics></math> algebra that can be viewed as an extension of the Chekanov–Eliashberg differential graded algebra. The <math>\u0000 <semantics>\u0000 <msub>\u0000 <mi>L</mi>\u0000 <mi>∞</mi>\u0000 </msub>\u0000 <annotation>$L_infty$</annotation>\u0000 </semantics></math> structure incorporates information from rational symplectic field theory and can be formulated combinatorially. One consequence is the construction of a Poisson bracket on commutative Legendrian contact homology, and we show that the resulting Poisson algebra is an invariant of Legendrian links under isotopy.","PeriodicalId":56114,"journal":{"name":"Journal of Topology","volume":"18 3","pages":""},"PeriodicalIF":1.1,"publicationDate":"2025-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144740506","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Effect of advection on the predator-prey dynamics with a drift-feeding predator 平流对漂食捕食者捕食动力学的影响

IF 2.3 2区数学

Journal of Differential Equations Pub Date : 2025-07-31 DOI: 10.1016/j.jde.2025.113660

Biao Wang , Hao Wang

引用次数: 0

Discrete selectivity and disjoint local π-bases 离散选择性和不相交局部π基

IF 0.5 4区数学

Topology and its Applications Pub Date : 2025-07-31 DOI: 10.1016/j.topol.2025.109534

Hector Barriga-Acosta, Alan Dow

引用次数: 0

Dimension Reduction for Large-Scale Federated Data: Statistical Rate and Asymptotic Inference 大规模联邦数据的降维：统计率和渐近推断

IF 3.7 1区数学

Journal of the American Statistical Association Pub Date : 2025-07-31 DOI: 10.1080/01621459.2025.2537453

Shuting Shen, Junwei Lu, Xihong Lin

引用次数: 0

On the effects of spatial heterogeneity on positive steady states of Lotka-Volterra competition model with advection 空间异质性对带平流的Lotka-Volterra竞争模式正稳态的影响

IF 2.3 2区数学

Journal of Differential Equations Pub Date : 2025-07-31 DOI: 10.1016/j.jde.2025.113657

Yaying Dong , Xueqian Zhou , Shanbing Li

引用次数: 0