{"title":"Stability of A(mathbb{T})-relations in (C^*)-algebras with tracial rank at most one","authors":"J. Hua","doi":"10.1007/s10476-026-00139-3","DOIUrl":"10.1007/s10476-026-00139-3","url":null,"abstract":"<div><p>An old and famous problem from the 1950s, popularized by Halmos, is that whether any pair of almost commuting contractive self-adjoint matrices are norm close to a pair of exactly commuting self-adjoint matrices? This question was solved affirmatively by Lin in the 1990's. In this paper, we study the general Halmos problem concerning unitary elements in <span>(C^*)</span>-algebras. Specifically, we first introduce the definition of A<span>(mathbb{T})</span>-relations, and then we give a necessary and sufficient condition for the stability of A<span>(mathbb{T})</span>-relations in any unital infinite\u0000dimensional simple separable <span>(C^*)</span>-algebra with tracial rank at most one. Finally, as applications, we show that many naturally occurring relations are A<span>(mathbb{T})</span>-relations, and thus the stability results of these relations can be obtained by applying the above conclusions.</p></div>","PeriodicalId":55518,"journal":{"name":"Analysis Mathematica","volume":"52 1","pages":"117 - 151"},"PeriodicalIF":0.5,"publicationDate":"2026-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147665677","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":"Optimality conditions for change of variable operators in Sobolev spaces with mixed derivatives","authors":"V. K. Nguyen","doi":"10.1007/s10476-026-00141-9","DOIUrl":"10.1007/s10476-026-00141-9","url":null,"abstract":"<div><p>Change of variable plays an important role in constructing sparse grids for multivariate numerical integration of functions on \u0000<span>([0,1]^d)</span>. This is a modification of \u0000cubature formulae for functions supported in <span>([0,1]^d)</span> \u0000which yields the same order of convergence. \u0000In this paper we prove the necessary and sufficient conditions for the continuity of the change of variable operator in the Sobolev space with \u0000mixed derivatives <span>(boldsymbol{W}_p^m (mathbb{R}^d))</span>\u0000 with <span>(1leq p<infty)</span>\u0000 . The result is then extended to the spaces on the unit cube \u0000 <span>(boldsymbol{W}_p^m([0,1]^d))</span>.</p></div>","PeriodicalId":55518,"journal":{"name":"Analysis Mathematica","volume":"52 1","pages":"291 - 306"},"PeriodicalIF":0.5,"publicationDate":"2026-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147665673","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":"A note on the conjugates of nuclear operators","authors":"M. Nowak","doi":"10.1007/s10476-026-00142-8","DOIUrl":"10.1007/s10476-026-00142-8","url":null,"abstract":"<div><p>Let <span>((Omega,Sigma,mu))</span> be a finite measure space and <i>X</i> and <i>Y</i> be real Banach spaces. It is shown that if <span>(T colon L^infty(mu,X)rightarrow Y)</span> is a <span>(sigma )</span>-order continuous\u0000operator and <span>(X ^{*} )</span> has the Radon-Nikodym property, <i>Y</i> is reflexive, then <i>T</i>\u0000is a nuclear operator if and only if its conjugate operator\u0000<span>(T ^{*} :Y ^{*} rightarrow L^1(mu,X ^{*} ))</span> is nuclear. In this case, <span>(|T| _{rm nuc}=|T ^{*} | _{rm nuc})</span>.\u0000</p></div>","PeriodicalId":55518,"journal":{"name":"Analysis Mathematica","volume":"52 1","pages":"333 - 341"},"PeriodicalIF":0.5,"publicationDate":"2026-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147665737","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":"Calderón–Zygmund operators and commutators on weighted Hardy spaces","authors":"Y. Han, F. Liu, H. Wu","doi":"10.1007/s10476-026-00138-4","DOIUrl":"10.1007/s10476-026-00138-4","url":null,"abstract":"<div><p>Two classes of Hörmander type conditions are introduced in the present paper. These conditions are weaker strictly than the classical standard Calderón–Zygmund kernels. A systematical study is given for the bounds of the Calderón–Zygmund operator with the above Hörmander type kernels and their commutators on the weighted Hardy spaces. The main results of this paper essentially improve a large classes of classical works. It should be pointed out that the main results are new, even in the unweighted case.</p></div>","PeriodicalId":55518,"journal":{"name":"Analysis Mathematica","volume":"52 1","pages":"87 - 115"},"PeriodicalIF":0.5,"publicationDate":"2026-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147665729","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":"On the local regularity of the Hilbert transform","authors":"Y. Pan, J. Wang, Y. Yan","doi":"10.1007/s10476-025-00137-x","DOIUrl":"10.1007/s10476-025-00137-x","url":null,"abstract":"<div><p>In this paper the local regularity of the Hilbert transform is studied, and local smoothness and real analyticity results are obtained.</p></div>","PeriodicalId":55518,"journal":{"name":"Analysis Mathematica","volume":"52 1","pages":"343 - 374"},"PeriodicalIF":0.5,"publicationDate":"2026-01-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10476-025-00137-x.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147665618","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Bounds and asymptotic expansions for the radii of convexity and uniform convexity of normalized Bessel functions","authors":"Á. Baricz, P. Kumar, S. Singh","doi":"10.1007/s10476-025-00136-y","DOIUrl":"10.1007/s10476-025-00136-y","url":null,"abstract":"<div><p>This paper explores the asymptotic behavior of the radii of convexity and uniform convexity for normalized Bessel functions with respect to large order. We provide detailed asymptotic expansions for these radii and establish recurrence relations for the associated coefficients. Additionally, we derive generalized bounds for the radii of convexity and uniform convexity by applying the Euler–Rayleigh inequality and potential polynomials. The asymptotic inversion method and Rayleigh sums are the main tools used in the proofs.</p></div>","PeriodicalId":55518,"journal":{"name":"Analysis Mathematica","volume":"52 1","pages":"1 - 43"},"PeriodicalIF":0.5,"publicationDate":"2026-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147665736","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":"Equality in Liakopoulos's generalized dual Loomis-Whitney inequality via Barthe's Reverse Brascamp-Lieb inequality","authors":"K. J. Böröczky, F. Fodor, P. Kalantzopoulos","doi":"10.1007/s10476-025-00134-0","DOIUrl":"10.1007/s10476-025-00134-0","url":null,"abstract":"<div><p>We use the characterization of the case of equality in Barthe's geometric reverse Brascamp-Lieb inequality to characterize equality in Liakopoulos's volume estimate in terms of sections by certain lower-dimensional linear subspaces.</p></div>","PeriodicalId":55518,"journal":{"name":"Analysis Mathematica","volume":"51 4","pages":"1229 - 1245"},"PeriodicalIF":0.5,"publicationDate":"2025-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145766276","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":"Finely holomorphic functions in one and more complex variables-a survey","authors":"M. El Kadiri","doi":"10.1007/s10476-025-00135-z","DOIUrl":"10.1007/s10476-025-00135-z","url":null,"abstract":"<div><p>This paper is a survey on the theory of finely holomorphic\u0000functions in one variable as developed by Fuglede in the 1980s and\u0000in several variables as developed recently by El Kadiri, Fuglede and Wiegerinck. Some applications to pluripotential theory are also given.\u0000</p></div>","PeriodicalId":55518,"journal":{"name":"Analysis Mathematica","volume":"51 4","pages":"1247 - 1266"},"PeriodicalIF":0.5,"publicationDate":"2025-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145766280","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":"Normal operators in real and quaternionic Hilbert spaces","authors":"F.-H. Vasilescu","doi":"10.1007/s10476-025-00132-2","DOIUrl":"10.1007/s10476-025-00132-2","url":null,"abstract":"<div><p>A new approach to normal operators in real Hilbert spaces is\u0000discussed, and a spectral representation is obtained, derived directly from the\u0000complex case. The results are then applied to quaternionic normal operators,\u0000regarded as a special class of real normal operators. This point of view allows us\u0000to consider their spectrum and associated measures to be defined on subsets of\u0000the complex plane, in a classical manner.\u0000</p></div>","PeriodicalId":55518,"journal":{"name":"Analysis Mathematica","volume":"51 4","pages":"1455 - 1485"},"PeriodicalIF":0.5,"publicationDate":"2025-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145766244","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}
C. Berg, K. Böröczky, M. El Kadiri, M. Kolountzakis, N. Zorii, L. Zsidó
{"title":"Selected gems from the mathematics of Bent Fuglede - a centenary tribute","authors":"C. Berg, K. Böröczky, M. El Kadiri, M. Kolountzakis, N. Zorii, L. Zsidó","doi":"10.1007/s10476-025-00124-2","DOIUrl":"10.1007/s10476-025-00124-2","url":null,"abstract":"","PeriodicalId":55518,"journal":{"name":"Analysis Mathematica","volume":"51 4","pages":"1117 - 1154"},"PeriodicalIF":0.5,"publicationDate":"2025-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145766278","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}