{"title":"Jordan mating is always possible for polynomials","authors":"","doi":"10.1007/s00209-024-03465-0","DOIUrl":"https://doi.org/10.1007/s00209-024-03465-0","url":null,"abstract":"<h3>Abstract</h3> <p>Suppose <em>f</em> and <em>g</em> are two post-critically finite polynomials of degree <span> <span>(d_1)</span> </span> and <span> <span>(d_2)</span> </span> respectively and suppose both of them have a finite super-attracting fixed point of degree <span> <span>(d_0)</span> </span>. We prove that one can always construct a rational map <em>R</em> of degree <span> <span>$$begin{aligned} D = d_1 + d_2 - d_0 end{aligned}$$</span> </span>by gluing <em>f</em> and <em>g</em> along the Jordan curve boundaries of the immediate super-attracting basins. The result can be used to construct many rational maps with interesting dynamics.</p>","PeriodicalId":18278,"journal":{"name":"Mathematische Zeitschrift","volume":"16 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2024-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140154301","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Bloom weighted bounds for sparse forms associated to commutators","authors":"Andrei K. Lerner, Emiel Lorist, Sheldy Ombrosi","doi":"10.1007/s00209-024-03471-2","DOIUrl":"https://doi.org/10.1007/s00209-024-03471-2","url":null,"abstract":"<p>In this paper we consider bilinear sparse forms intimately related to iterated commutators of a rather general class of operators. We establish Bloom weighted estimates for these forms in the full range of exponents, both in the diagonal and off-diagonal cases. As an application, we obtain new Bloom bounds for commutators of (maximal) rough homogeneous singular integrals and the Bochner–Riesz operator at the critical index. We also raise the question about the sharpness of our estimates. In particular we obtain the surprising fact that even in the case of Calderón–Zygmund operators, the previously known quantitative Bloom bounds are not sharp for the second and higher order commutators.</p>","PeriodicalId":18278,"journal":{"name":"Mathematische Zeitschrift","volume":"147 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2024-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140154118","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Ill-posedness for the Half wave Schrödinger equation","authors":"Isao Kato","doi":"10.1007/s00209-024-03452-5","DOIUrl":"https://doi.org/10.1007/s00209-024-03452-5","url":null,"abstract":"<p>We study the Cauchy problem for the half wave Schrödinger equation introduced by Xu [9]. There are some well-posedness results for the equation, however there is no ill-posedness result. We focus on the scale critical space and obtain the ill-posedness in the super-critical or at the critical space under certain condition. The proofs in the super-critical space are based on the argument established by Christ, Colliander and Tao [4]. More precisely, we analyze dispersionless equation with smooth initial data, namely the Schwartz function and it is locally well-posed in some weighted Sobolev space. We construct the solution for the half wave Schrödinger equation by using the solution for the dispersionless equation and we can exploit the norm inflation or the decoherence properties. For the critical space, we use the standing wave solution, which was proved the existence by Bahri, Ibrahim and Kikuchi [1].</p>","PeriodicalId":18278,"journal":{"name":"Mathematische Zeitschrift","volume":"30 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2024-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140154237","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Cohomology and geometry of Deligne–Lusztig varieties for $$textrm{GL}_n$$","authors":"Yingying Wang","doi":"10.1007/s00209-024-03455-2","DOIUrl":"https://doi.org/10.1007/s00209-024-03455-2","url":null,"abstract":"<p>We give a description of the cohomology groups of the structure sheaf on smooth compactifications <span>(overline{X}(w))</span> of Deligne–Lusztig varieties <i>X</i>(<i>w</i>) for <span>(textrm{GL}_n)</span>, for all elements <i>w</i> in the Weyl group. As a consequence, we obtain the <span>(textrm{mod} p^m)</span> and integral <i>p</i>-adic étale cohomology of <span>(overline{X}(w))</span>. Moreover, using our result for <span>(overline{X}(w))</span> and a spectral sequence associated to a stratification of <span>(overline{X}(w))</span>, we deduce the <span>(textrm{mod} p^m)</span> and integral <i>p</i>-adic étale cohomology with compact support of <i>X</i>(<i>w</i>). In our proof of the main theorem, in addition to considering the Demazure–Hansen smooth compactifications of <i>X</i>(<i>w</i>), we show that a similar class of constructions provide smooth compactifications of <i>X</i>(<i>w</i>) in the case of <span>(textrm{GL}_n)</span>. Furthermore, we show in the appendix that the Zariski closure of <i>X</i>(<i>w</i>), for any connected reductive group <i>G</i> and any <i>w</i>, has pseudo-rational singularities.</p>","PeriodicalId":18278,"journal":{"name":"Mathematische Zeitschrift","volume":"10 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2024-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140154114","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"D-finiteness, rationality, and height III: multivariate Pólya–Carlson dichotomy","authors":"Jason P. Bell, Shaoshi Chen, Khoa D. Nguyen, Umberto Zannier","doi":"10.1007/s00209-024-03470-3","DOIUrl":"https://doi.org/10.1007/s00209-024-03470-3","url":null,"abstract":"<p>We prove a result that can be seen as an analogue of the Pólya–Carlson theorem for multivariate D-finite power series with coefficients in <span>(bar{mathbb {Q}})</span>. In the special case that the coefficients are algebraic integers, our main result says that if </p><span>$$begin{aligned} F(x_1,ldots ,x_m)=sum f(n_1,ldots ,n_m)x_1^{n_1}cdots x_m^{n_m} end{aligned}$$</span><p>is a D-finite power series in <i>m</i> variables with algebraic integer coefficients and if the logarithmic Weil height of <span>(f(n_1,ldots ,n_m))</span> is <span>(o(n_1+cdots +n_m))</span>, then <i>F</i> is a rational function and, up to scalar multiplication, every irreducible factor of the denominator of <i>F</i> has the form <span>(1-zeta x_1^{q_1}cdots x_m^{q_m})</span> where <span>(zeta )</span> is a root of unity and <span>(q_1,ldots ,q_m)</span> are nonnegative integers, not all of which are zero.</p>","PeriodicalId":18278,"journal":{"name":"Mathematische Zeitschrift","volume":"68 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2024-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140154300","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Matrix Kloosterman sums modulo prime powers","authors":"M. Erdélyi, Á. Tóth, G. Zábrádi","doi":"10.1007/s00209-024-03467-y","DOIUrl":"https://doi.org/10.1007/s00209-024-03467-y","url":null,"abstract":"<p>We give optimal bounds for matrix Kloosterman sums modulo prime powers extending earlier work of the first two authors on the case of prime moduli. These exponential sums arise in the theory of the horocyclic flow on <span>(GL_n)</span>.</p>","PeriodicalId":18278,"journal":{"name":"Mathematische Zeitschrift","volume":"123 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2024-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140154243","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Whittaker categories and the minimal nilpotent finite W-algebras for $$mathfrak {sl}_{n+1}$$","authors":"Genqiang Liu, Yang Li","doi":"10.1007/s00209-024-03469-w","DOIUrl":"https://doi.org/10.1007/s00209-024-03469-w","url":null,"abstract":"<p>For any <span>({textbf{a}}=(a_1,dots ,a_n)in {mathbb {C}}^n)</span>, we introduce a Whittaker category <span>({mathcal {H}}_{{textbf{a}}})</span> whose objects are <span>(mathfrak {sl}_{n+1})</span>-modules <i>M</i> such that <span>(e_{0i}-a_i)</span> acts locally nilpotently on <i>M</i> for all <span>(i in {1,dots ,n})</span>, and the subspace <span>(textrm{wh}_{{textbf{a}}}(M)={vin M mid e_{0i} v=a_iv, i=1,dots ,n})</span> is finite dimensional. In this paper, we first give a tensor product decomposition <span>(U_S=Wotimes B)</span> of the localization <span>(U_S)</span> of <span>(U(mathfrak {sl}_{n+1}))</span> with respect to the Ore subset <i>S</i> generated by <span>(e_{01},dots , e_{0n})</span>. We show that the associative algebra <i>W</i> is isomorphic to the type <span>(A_n)</span> finite <i>W</i>-algebra <i>W</i>(<i>e</i>) defined by a minimal nilpotent element <i>e</i> in <span>(mathfrak {sl}_{n+1})</span>. Then using <i>W</i>-modules as a bridge, we show that each block with a generalized central character of <span>({mathcal {H}}_{{textbf{1}}})</span> is equivalent to the corresponding block of the cuspidal category <span>({mathcal {C}})</span>, which is completely characterized by Grantcharov and Serganova. As a consequence, each regular integral block of <span>({mathcal {H}}_{{textbf{1}}})</span> and the category of finite dimensional modules over <i>W</i>(<i>e</i>) can be described by a well-studied quiver with certain quadratic relations.</p>","PeriodicalId":18278,"journal":{"name":"Mathematische Zeitschrift","volume":"49 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2024-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140115669","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Nonempty interior of configuration sets via microlocal partition optimization","authors":"Allan Greenleaf, Alex Iosevich, Krystal Taylor","doi":"10.1007/s00209-024-03466-z","DOIUrl":"https://doi.org/10.1007/s00209-024-03466-z","url":null,"abstract":"<p>We prove new results of Mattila–Sjölin type, giving lower bounds on Hausdorff dimensions of thin sets <span>(Esubset mathbb {R}^d)</span> ensuring that various <i>k</i>-point configuration sets, generated by elements of <i>E</i>, have nonempty interior. The dimensional thresholds in our previous work (Greenleaf et al., Mathematika 68(1):163–190, 2022) were dictated by associating to a configuration function a family of generalized Radon transforms, and then optimizing <span>(L^2)</span>-Sobolev estimates for them over all nontrivial bipartite partitions of the <i>k</i> points. In the current work, we extend this by allowing the optimization to be done locally over the configuration’s incidence relation, or even microlocally over the conormal bundle of the incidence relation. We use this approach to prove Mattila–Sjölin type results for (i) areas of subtriangles determined by quadrilaterals and pentagons in a set <span>(Esubset mathbb {R}^2)</span>; (ii) pairs of ratios of distances of 4-tuples in <span>(mathbb {R}^d)</span>; and (iii) similarity classes of triangles in <span>(mathbb {R}^d)</span>, as well as to (iv) give a short proof of Palsson and Romero Acosta’s result on congruence classes of triangles in <span>(mathbb {R}^d)</span>.</p>","PeriodicalId":18278,"journal":{"name":"Mathematische Zeitschrift","volume":"83 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2024-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140115298","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Canonical integral operators on the Fock space","authors":"Xingtang Dong, Kehe Zhu","doi":"10.1007/s00209-024-03463-2","DOIUrl":"https://doi.org/10.1007/s00209-024-03463-2","url":null,"abstract":"<p>In this paper we introduce and study a two-parameter family of integral operators on the Fock space <span>(F^2({mathbb {C}}))</span>. We determine exactly when these operators are bounded and when they are unitary. We show that, under the Bargmann transform, these operators include the classical linear canonical transforms as special cases. As an application, we obtain a new unitary projective representation for the special linear group <span>(SL(2,{mathbb {R}}))</span> on the Fock space.</p>","PeriodicalId":18278,"journal":{"name":"Mathematische Zeitschrift","volume":"39 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2024-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140117601","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Rank-one perturbations and norm-attaining operators","authors":"","doi":"10.1007/s00209-024-03458-z","DOIUrl":"https://doi.org/10.1007/s00209-024-03458-z","url":null,"abstract":"<h3>Abstract</h3> <p>The main goal of this article is to show that for every (reflexive) infinite-dimensional Banach space <em>X</em> there exists a reflexive Banach space <em>Y</em> and <span> <span>(T, R in mathcal {L}(X,Y))</span> </span> such that <em>R</em> is a rank-one operator, <span> <span>(Vert T+RVert >Vert TVert )</span> </span> but <span> <span>(T+R)</span> </span> does not attain its norm. This answers a question posed by Dantas and the first two authors. Furthermore, motivated by the parallelism exhibited in the literature between the <em>V</em>-property introduced by Khatskevich, Ostrovskii and Shulman and the weak maximizing property introduced by Aron, García, Pellegrino and Teixeira, we also study the relationship between these two properties and norm-attaining perturbations of operators.</p>","PeriodicalId":18278,"journal":{"name":"Mathematische Zeitschrift","volume":"37 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2024-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140074236","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}