Pub Date : 2024-09-19DOI: 10.1007/s00208-024-02985-8
Spencer Cattalani
A taming symplectic structure provides an upper bound on the area of an approximately pseudoholomorphic curve in terms of its homology class. We prove that, conversely, an almost complex manifold with such an area bound admits a taming symplectic structure. This confirms a speculation by Gromov. We also characterize the cone of taming symplectic structures numerically, prove that complex 2-cycles can be approximated by coarsely holomorphic curves, and provide a lower energy bound for such curves.
{"title":"Coarsely holomorphic curves and symplectic topology","authors":"Spencer Cattalani","doi":"10.1007/s00208-024-02985-8","DOIUrl":"https://doi.org/10.1007/s00208-024-02985-8","url":null,"abstract":"<p>A taming symplectic structure provides an upper bound on the area of an approximately pseudoholomorphic curve in terms of its homology class. We prove that, conversely, an almost complex manifold with such an area bound admits a taming symplectic structure. This confirms a speculation by Gromov. We also characterize the cone of taming symplectic structures numerically, prove that complex 2-cycles can be approximated by coarsely holomorphic curves, and provide a lower energy bound for such curves.\u0000</p>","PeriodicalId":18304,"journal":{"name":"Mathematische Annalen","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142248056","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}
Pub Date : 2024-09-17DOI: 10.1007/s00208-024-02971-0
Valeria Banica, Daniel Eceizabarrena, Andrea R. Nahmod, Luis Vega
With the aim of quantifying turbulent behaviors of vortex filaments, we study the multifractality and intermittency of the family of generalized Riemann’s non-differentiable functions
$$begin{aligned} R_{x_0}(t) = sum _{n ne 0} frac{e^{2pi i ( n^2 t + n x_0 ) } }{n^2}, qquad x_0 in [0,1]. end{aligned}$$
These functions represent, in a certain limit, the trajectory of regular polygonal vortex filaments that evolve according to the binormal flow. When (x_0) is rational, we show that (R_{x_0}) is multifractal and intermittent by completely determining the spectrum of singularities of (R_{x_0}) and computing the (L^p) norms of its Fourier high-pass filters, which are analogues of structure functions. We prove that (R_{x_0}) has a multifractal behavior also when (x_0) is irrational. The proofs rely on a careful design of Diophantine sets that depend on (x_0), which we study by using the Duffin–Schaeffer theorem and the Mass Transference Principle.
为了量化涡旋丝的湍流行为,我们研究了广义黎曼无差异函数$$begin{aligned}族的多重性和间歇性。R_{x_0}(t) = sum _{n ne 0} frac{e^{2pi i ( n^2 t + n x_0 ) } }{n^2}, frac{e^{2pi i ( n^2 t + n x_0 ) } }{n^2}.}{n^2}, qquad x_0 in [0,1].end{aligned}$$这些函数在一定限度内代表了根据二正态流演化的规则多边形涡旋丝的轨迹。当 (x_0) 是有理数时,我们通过完全确定 (R_{x_0}) 的奇点谱并计算其傅里叶高通滤波器的 (L^p) 准则(它们是结构函数的类似物),证明 (R_{x_0}) 是多分形和间歇的。我们证明了当(x_0)是无理数时,(R_{x_0})也具有多分形行为。证明依赖于对依赖于 (x_0) 的 Diophantine 集的精心设计,我们利用 Duffin-Schaeffer 定理和质量转移原理对其进行了研究。
{"title":"Multifractality and intermittency in the limit evolution of polygonal vortex filaments","authors":"Valeria Banica, Daniel Eceizabarrena, Andrea R. Nahmod, Luis Vega","doi":"10.1007/s00208-024-02971-0","DOIUrl":"https://doi.org/10.1007/s00208-024-02971-0","url":null,"abstract":"<p>With the aim of quantifying turbulent behaviors of vortex filaments, we study the multifractality and intermittency of the family of generalized Riemann’s non-differentiable functions </p><span>$$begin{aligned} R_{x_0}(t) = sum _{n ne 0} frac{e^{2pi i ( n^2 t + n x_0 ) } }{n^2}, qquad x_0 in [0,1]. end{aligned}$$</span><p>These functions represent, in a certain limit, the trajectory of regular polygonal vortex filaments that evolve according to the binormal flow. When <span>(x_0)</span> is rational, we show that <span>(R_{x_0})</span> is multifractal and intermittent by completely determining the spectrum of singularities of <span>(R_{x_0})</span> and computing the <span>(L^p)</span> norms of its Fourier high-pass filters, which are analogues of structure functions. We prove that <span>(R_{x_0})</span> has a multifractal behavior also when <span>(x_0)</span> is irrational. The proofs rely on a careful design of Diophantine sets that depend on <span>(x_0)</span>, which we study by using the Duffin–Schaeffer theorem and the Mass Transference Principle.</p>","PeriodicalId":18304,"journal":{"name":"Mathematische Annalen","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142248055","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}
Pub Date : 2024-09-17DOI: 10.1007/s00208-024-02996-5
Hebai Chen, Jie Jin, Zhaoxia Wang, Dongmei Xiao
This paper is to provide a criterion of the uniqueness of periodic solutions for a Rayleigh-Liénard system with state-dependent impulses. Notice that such results of a planar system with state-dependent impulses are few. Moreover, the Rayleigh-Liénard system with state-dependent impulses has wide applications, such as a simple pendulum and a spring vibrator. Further, we obtain the uniqueness of periodic solutions of the simple pendulum with state-dependent impulses and the spring vibrator with state-dependent impulses by the criterion.
{"title":"On the uniqueness of periodic solutions for a Rayleigh–Liénard system with impulses","authors":"Hebai Chen, Jie Jin, Zhaoxia Wang, Dongmei Xiao","doi":"10.1007/s00208-024-02996-5","DOIUrl":"https://doi.org/10.1007/s00208-024-02996-5","url":null,"abstract":"<p>This paper is to provide a criterion of the uniqueness of periodic solutions for a Rayleigh-Liénard system with state-dependent impulses. Notice that such results of a planar system with state-dependent impulses are few. Moreover, the Rayleigh-Liénard system with state-dependent impulses has wide applications, such as a simple pendulum and a spring vibrator. Further, we obtain the uniqueness of periodic solutions of the simple pendulum with state-dependent impulses and the spring vibrator with state-dependent impulses by the criterion.</p>","PeriodicalId":18304,"journal":{"name":"Mathematische Annalen","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142248053","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}
Pub Date : 2024-09-12DOI: 10.1007/s00208-024-02959-w
Isaac Goldbring, David Jekel, Srivatsav Kunnawalkam Elayavalli, Jennifer Pi
We introduce and study the family of uniformly super McDuff (hbox {II}_1) factors. This family is shown to be closed under elementary equivalence and also coincides with the family of (hbox {II}_1) factors with the Brown property introduced in Atkinson et al. (Adv. Math. 396, 108107, 2022). We show that a certain family of existentially closed factors, the so-called infinitely generic factors, are uniformly super McDuff, thereby improving a recent result of Chifan et al. (Embedding Universality for (hbox {II}_1) Factors with Property (T). arXiv preprint, 2022). We also show that Popa’s family of strongly McDuff (hbox {II}_1) factors are uniformly super McDuff. Lastly, we investigate when finitely generic (hbox {II}_1) factors are uniformly super McDuff.
{"title":"Uniformly super McDuff $$hbox {II}_1$$ factors","authors":"Isaac Goldbring, David Jekel, Srivatsav Kunnawalkam Elayavalli, Jennifer Pi","doi":"10.1007/s00208-024-02959-w","DOIUrl":"https://doi.org/10.1007/s00208-024-02959-w","url":null,"abstract":"<p>We introduce and study the family of uniformly super McDuff <span>(hbox {II}_1)</span> factors. This family is shown to be closed under elementary equivalence and also coincides with the family of <span>(hbox {II}_1)</span> factors with the Brown property introduced in Atkinson et al. (Adv. Math. 396, 108107, 2022). We show that a certain family of existentially closed factors, the so-called infinitely generic factors, are uniformly super McDuff, thereby improving a recent result of Chifan et al. (Embedding Universality for <span>(hbox {II}_1)</span> Factors with Property (T). arXiv preprint, 2022). We also show that Popa’s family of strongly McDuff <span>(hbox {II}_1)</span> factors are uniformly super McDuff. Lastly, we investigate when finitely generic <span>(hbox {II}_1)</span> factors are uniformly super McDuff.</p>","PeriodicalId":18304,"journal":{"name":"Mathematische Annalen","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142185182","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}
where (a,b,c>0), (mu in {mathbb {R}}) and (2<q<6), (lambda in {mathbb {R}}) will arise as a Lagrange multiplier that is not a priori given. By using new analytical techniques, the paper establishes several existence results for the case (mu >0):