{"title":"Microlocal decoupling inequalities and the distance problem on Riemannian manifolds","authors":"A. Iosevich, Bochen Liu, Yakun Xi","doi":"10.1353/ajm.2022.0039","DOIUrl":"https://doi.org/10.1353/ajm.2022.0039","url":null,"abstract":"abstract:We study the generalization of the Falconer distance problem to the Riemannian setting. In particular, we extend the result of Guth--Iosevich--Ou--Wang for the distance set in the plane to general Riemannian surfaces. Key new ingredients include a family of refined microlocal decoupling inequalities, which are related to the work of Beltran--Hickman--Sogge on Wolff-type inequalities, and an analog of Orponen's radial projection lemma which has proved quite useful in recent work on distance sets.","PeriodicalId":7453,"journal":{"name":"American Journal of Mathematics","volume":"144 1","pages":"1601 - 1639"},"PeriodicalIF":1.7,"publicationDate":"2019-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42530950","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}
{"title":"Noncommutative tensor triangular geometry","authors":"D. Nakano, Kent B. Vashaw, M. Yakimov","doi":"10.1353/ajm.2022.0041","DOIUrl":"https://doi.org/10.1353/ajm.2022.0041","url":null,"abstract":"abstract:We develop a general noncommutative version of Balmer's tensor triangular geometry that is applicable to arbitrary monoidal triangulated categories (M$Delta$Cs). Insight from noncommutative ring theory is used to obtain a framework for prime, semiprime, and completely prime (thick) ideals of an M$Delta$C, ${bf K}$, and then to associate to ${bf K}$ a topological space--the Balmer spectrum ${rm Spc}{bf K}$. We develop a general framework for (noncommutative) support data, coming in three different flavors, and show that ${rm Spc}{bf K}$ is a universal terminal object for the first two notions (support and weak support). The first two types of support data are then used in a theorem that gives a method for the explicit classification of the thick (two-sided) ideals and the Balmer spectrum of an M$Delta$C. The third type (quasi support) is used in another theorem that provides a method for the explicit classification of the thick right ideals of ${bf K}$, which in turn can be applied to classify the thick two-sided ideals and ${rm Spc}{bf K}$.As a special case, our approach can be applied to the stable module categories of arbitrary finite dimensional Hopf algebras that are not necessarily cocommutative (or quasitriangular). We illustrate the general theorems with classifications of the Balmer spectra and thick two-sided/right ideals for the stable module categories of all small quantum groups for Borel subalgebras, and classifications of the Balmer spectra and thick two-sided ideals of Hopf algebras studied by Benson and Witherspoon.","PeriodicalId":7453,"journal":{"name":"American Journal of Mathematics","volume":"144 1","pages":"1681 - 1724"},"PeriodicalIF":1.7,"publicationDate":"2019-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48118546","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}
{"title":"Circle patterns on surfaces of finite topological type","authors":"Huabin Ge, B. Hua, Ze‐hua Zhou","doi":"10.2140/pjm.2020.306.203","DOIUrl":"https://doi.org/10.2140/pjm.2020.306.203","url":null,"abstract":"Abstract:This paper investigates circle patterns with obtuse exterior intersection angles on surfaces of finite topological type. We characterise the images of the curvature maps and establish several equivalent conditions regarding long time behaviors of Chow-Luo's combinatorial Ricci flows for these patterns. As consequences, several generalizations of circle pattern theorem are obtained. Moreover, our approach suggests a computational method to find the desired circle patterns.","PeriodicalId":7453,"journal":{"name":"American Journal of Mathematics","volume":"143 1","pages":"1397 - 1430"},"PeriodicalIF":1.7,"publicationDate":"2019-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2140/pjm.2020.306.203","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47712611","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}
{"title":"Cancellation in the additive twists of Fourier coefficients for GL2 and GL3 over number fields","authors":"Zhi Qi","doi":"10.1353/ajm.2019.0034","DOIUrl":"https://doi.org/10.1353/ajm.2019.0034","url":null,"abstract":"abstract:In this article, we study the sum of additively twisted Fourier coefficients of an irreducible cuspidal automorphic representation of ${rm GL}_2$ or ${rm GL}_3$ over an arbitrary number field. When the representation is unramified at all non-archimedean places, we prove the Wilton type bound for ${rm GL}_2$ and the Miller type bound for ${rm GL}_3$ which are uniform in terms of the additive character.","PeriodicalId":7453,"journal":{"name":"American Journal of Mathematics","volume":"141 1","pages":"1317 - 1345"},"PeriodicalIF":1.7,"publicationDate":"2019-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1353/ajm.2019.0034","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45876879","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}
{"title":"Existence of minimal hypersurfaces with non-empty free Boundary for generic metrics","authors":"Zhichao Wang","doi":"10.1353/ajm.2022.0012","DOIUrl":"https://doi.org/10.1353/ajm.2022.0012","url":null,"abstract":"abstract:For almost all Riemannian metrics (in the $C^infty$ Baire sense) on a compact manifold with boundary $(M^{n+1},breakpartial M)$, $3leq (n+1)leq 7$, we prove that, for any open subset $V$ of $partial M$, there exists a compact, properly embedded free boundary minimal hypersurface intersecting $V$.","PeriodicalId":7453,"journal":{"name":"American Journal of Mathematics","volume":"144 1","pages":"599 - 606"},"PeriodicalIF":1.7,"publicationDate":"2019-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44915975","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}
{"title":"Law of large numbers for the spectral radius of random matrix products","authors":"Richard Aoun, Cagri Sert","doi":"10.1353/AJM.2021.0025","DOIUrl":"https://doi.org/10.1353/AJM.2021.0025","url":null,"abstract":"abstract:We prove that the spectral radius of an i.i.d. random walk on ${rm GL}_d(Bbb{C})$ satisfies a strong law of large numbers under finite second moment assumption and a weak law of large numbers under finite first moment. No irreducibility assumption is supposed.","PeriodicalId":7453,"journal":{"name":"American Journal of Mathematics","volume":"143 1","pages":"1010 - 995"},"PeriodicalIF":1.7,"publicationDate":"2019-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1353/AJM.2021.0025","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44503386","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}
{"title":"Improved bounds for the Kakeya maximal conjecture in higher dimensions","authors":"J. Hickman, K. Rogers, Ruixiang Zhang","doi":"10.1353/ajm.2022.0037","DOIUrl":"https://doi.org/10.1353/ajm.2022.0037","url":null,"abstract":"abstract:We adapt Guth's polynomial partitioning argument for the Fourier restriction problem to the context of the Kakeya problem. By writing out the induction argument as a recursive algorithm, additional multiscale geometric information is made available. To take advantage of this, we prove that direction-separated tubes satisfy a multiscale version of the polynomial Wolff axioms. Altogether, this yields improved bounds for the Kakeya maximal conjecture in~$Bbb{R}^n$ with $n=5$ or $nge 7$ and improved bounds for the Kakeya set conjecture for an infinite sequence of dimensions.","PeriodicalId":7453,"journal":{"name":"American Journal of Mathematics","volume":"144 1","pages":"1511 - 1560"},"PeriodicalIF":1.7,"publicationDate":"2019-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46979672","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}
{"title":"Structure and classification results for the ∞-elastica problem","authors":"R. Moser","doi":"10.1353/ajm.2022.0030","DOIUrl":"https://doi.org/10.1353/ajm.2022.0030","url":null,"abstract":"abstract:We consider the following variational problem: among all curves in $Bbb{R}^n$ of fixed length with prescribed end points and prescribed tangents at the end points, minimise the $L^infty$-norm of the curvature. We show that the solutions of this problem, and of a generalised version, are characterised by a system of differential equations. Furthermore, we have a lot of information about the structure of solutions, which allows a classification.","PeriodicalId":7453,"journal":{"name":"American Journal of Mathematics","volume":"144 1","pages":"1299 - 1329"},"PeriodicalIF":1.7,"publicationDate":"2019-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48233152","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}
{"title":"Dimension-Free Estimates for Discrete Hardy-Littlewood Averaging Operators Over the Cubes in ℤd","authors":"J. Bourgain, Mariusz Mirek, E. Stein, B. Wróbel","doi":"10.1353/ajm.2019.0023","DOIUrl":"https://doi.org/10.1353/ajm.2019.0023","url":null,"abstract":"abstract:Dimension-free bounds will be provided in maximal and $r$-variational inequalities on $ell^p({Bbb Z}^d)$ corresponding to the discrete Hardy-Littlewood averaging operators defined over the cubes in ${Bbb Z}^d$. We will also construct an example of a symmetric convex body in ${Bbb Z}^d$ for which maximal dimension-free bounds fail on $ell^p({Bbb Z}^d)$ for all $pin(1,infty)$. Finally, some applications in ergodic theory will be discussed.","PeriodicalId":7453,"journal":{"name":"American Journal of Mathematics","volume":"141 1","pages":"587 - 905"},"PeriodicalIF":1.7,"publicationDate":"2019-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1353/ajm.2019.0023","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48156591","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}