Hongchao Jia, Der-Chen Chang, Ferenc Weisz, Dachun Yang, Wen Yuan
{"title":"Musielak–Orlicz–Lorentz Hardy Spaces: Maximal Function, Finite Atomic, and Littlewood–Paley Characterizations with Applications to Dual Spaces and Summability of Fourier Transforms","authors":"Hongchao Jia, Der-Chen Chang, Ferenc Weisz, Dachun Yang, Wen Yuan","doi":"10.1007/s10114-025-3153-2","DOIUrl":"10.1007/s10114-025-3153-2","url":null,"abstract":"<div><p>Let <i>q</i> ∈ (0, ∞] and <i>φ</i> be a Musielak–Orlicz function with uniformly lower type <i>p</i><span>\u0000 <sup>−</sup><sub><i>φ</i></sub>\u0000 \u0000 </span> ∈ (0, ∞) and uniformly upper type <i>p</i><span>\u0000 <sup>+</sup><sub><i>φ</i></sub>\u0000 \u0000 </span> ∈ (0, ∞). In this article, the authors establish various real-variable characterizations of the Musielak–Orlicz–Lorentz Hardy space <i>H</i><sup><i>φ,q</i></sup>(ℝ<sup><i>n</i></sup>), respectively, in terms of various maximal functions, finite atoms, and various Littlewood–Paley functions. As applications, the authors obtain the dual space of <i>H</i><sup><i>φ,q</i></sup>(ℝ<sup><i>n</i></sup>) and the summability of Fourier transforms from <i>H</i><sup><i>φ,q</i></sup>(ℝ<sup><i>n</i></sup>) to the Musielak–Orlicz–Lorentz space <i>L</i><sup><i>φ,q</i></sup>(ℝ<sup><i>n</i></sup>) when <i>q</i> ∈ (0, ∞) or from the Musielak–Orlicz Hardy space <i>H</i><sup><i>φ</i></sup>(ℝ<sup><i>n</i></sup>) to <i>L</i><sup><i>φ,q</i></sup>(ℝ<sup><i>n</i></sup>) in the critical case. These results are new when <i>q</i> ∈ (0, ∞) and also essentially improve the existing corresponding results (if any) in the case <i>q</i> = ∞ via removing the original assumption that <i>φ</i> is concave. To overcome the essential obstacles caused by both that <i>φ</i> may not be concave and that the boundedness of the powered Hardy–Littlewood maximal operator on associated spaces of Musielak–Orlicz spaces is still unknown, the authors make full use of the obtained atomic characterization of <i>H</i><sup><i>φ,q</i></sup>(ℝ<sup><i>n</i></sup>), the corresponding results related to weighted Lebesgue spaces, and the subtle relation between Musielak–Orlicz spaces and weighted Lebesgue spaces.</p></div>","PeriodicalId":50893,"journal":{"name":"Acta Mathematica Sinica-English Series","volume":"41 1","pages":"1 - 77"},"PeriodicalIF":0.8,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143108863","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 Sense of Convergence in the Dyadic Representation Theorem","authors":"Tuomas Hytönen","doi":"10.1007/s10114-025-3698-0","DOIUrl":"10.1007/s10114-025-3698-0","url":null,"abstract":"<div><p>The dyadic representation of any singular integral operator, as an average of dyadic model operators, has found many applications. While for many purposes it is enough to have such a representation for a “suitable class” of test functions, we show that, under quite general assumptions (essentially minimal ones to make sense of the formula), the representation is actually valid for all pairs (<i>f,g</i>) ∈ <i>L</i><sup><i>p</i></sup>(ℝ<sup><i>d</i></sup>) × <i>L</i><sup><i>p</i>′</sup>(ℝ<sup><i>d</i></sup>), not just test functions.</p></div>","PeriodicalId":50893,"journal":{"name":"Acta Mathematica Sinica-English Series","volume":"41 1","pages":"472 - 496"},"PeriodicalIF":0.8,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143108855","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}
Dorothee D. Haroske, Leszek Skrzypczak, Hans Triebel
{"title":"Mapping Properties of Fourier Transforms, Revisited","authors":"Dorothee D. Haroske, Leszek Skrzypczak, Hans Triebel","doi":"10.1007/s10114-025-3532-8","DOIUrl":"10.1007/s10114-025-3532-8","url":null,"abstract":"<div><p>The paper deals with continuous and compact mappings generated by the Fourier transform between distinguished Besov spaces <i>B</i><span>\u0000 <sup><i>s</i></sup><sub><i>p</i></sub>\u0000 \u0000 </span>(ℝ<sup><i>n</i></sup>) = <i>B</i><span>\u0000 <sup><i>s</i></sup><sub><i>p,p</i></sub>\u0000 \u0000 </span>(ℝ<sup><i>n</i></sup>), 1 ≤ <i>p</i> ≤ ∞, and between Sobolev spaces <i>H</i><span>\u0000 <sup><i>s</i></sup><sub><i>p</i></sub>\u0000 \u0000 </span>(ℝ<sup><i>n</i></sup>), 1 < <i>p</i> < ∞. In contrast to the paper <i>H. Triebel, Mapping properties of Fourier transforms. Z. Anal. Anwend.</i> 41 (2022), 133–152, based mainly on embeddings between related weighted spaces, we rely on wavelet expansions, duality and interpolation of corresponding (unweighted) spaces, and (appropriately extended) Hausdorff-Young inequalities. The degree of compactness will be measured in terms of entropy numbers and approximation numbers, now using the symbiotic relationship to weighted spaces.</p></div>","PeriodicalId":50893,"journal":{"name":"Acta Mathematica Sinica-English Series","volume":"41 1","pages":"231 - 254"},"PeriodicalIF":0.8,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143108856","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":"Uniform Regularity for Degenerate Elliptic Equations in Perforated Domains","authors":"Zhongwei Shen, Jinping Zhuge","doi":"10.1007/s10114-025-3640-5","DOIUrl":"10.1007/s10114-025-3640-5","url":null,"abstract":"<div><p>This paper is concerned with a class of degenerate elliptic equations with rapidly oscillating coefficients in periodically perforated domains, which arises in the study of spectrum problems for uniformly elliptic equations in perforated domains. We establish a quantitative convergence rate and obtain the uniform weighted Lipschitz and <i>W</i><sup>1,<i>p</i></sup> estimates.</p></div>","PeriodicalId":50893,"journal":{"name":"Acta Mathematica Sinica-English Series","volume":"41 1","pages":"378 - 412"},"PeriodicalIF":0.8,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143108860","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 Remark on Stein–Tomas Type Restriction Theorems","authors":"Xiaochun Li","doi":"10.1007/s10114-025-3525-7","DOIUrl":"10.1007/s10114-025-3525-7","url":null,"abstract":"<div><p>A local <i>L</i><sup><i>p</i></sup> estimate is proved by using the <i>σ</i>-uniformity, which is motivated by the study of the Stein–Tomas type restriction theorems and Waring’s problem.</p></div>","PeriodicalId":50893,"journal":{"name":"Acta Mathematica Sinica-English Series","volume":"41 1","pages":"122 - 130"},"PeriodicalIF":0.8,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143108453","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":"New Characterization of Morrey-Herz Spaces and Morrey-Herz-Hardy Spaces with Applications to Various Linear Operators","authors":"Kwok Pun Ho, Yoshihiro Sawano","doi":"10.1007/s10114-025-3570-2","DOIUrl":"10.1007/s10114-025-3570-2","url":null,"abstract":"<div><p>This paper is an offspring of the previous study on Herz spaces. A new characterization of Morrey-Herz spaces is given. As applications, the boundedness of various operators is obtained. For example, higher-order commutators generated by singular integral operators and BMO functions are proved to be bounded on Morrey-Herz spaces. The theory of Morrey-Herz-Hardy spaces is also developed.</p></div>","PeriodicalId":50893,"journal":{"name":"Acta Mathematica Sinica-English Series","volume":"41 1","pages":"327 - 354"},"PeriodicalIF":0.8,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143108466","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}
Dorothee D. Haroske, Zhen Liu, Susana D. Moura, Leszek Skrzypczak
{"title":"Embeddings of Generalised Morrey Smoothness Spaces","authors":"Dorothee D. Haroske, Zhen Liu, Susana D. Moura, Leszek Skrzypczak","doi":"10.1007/s10114-025-3553-3","DOIUrl":"10.1007/s10114-025-3553-3","url":null,"abstract":"<div><p>We study embeddings between generalised Triebel–Lizorkin–Morrey spaces <span>(cal{E}_{varphi,p,q}^{s}(mathbb{R}^{d}))</span> and within the scales of further generalised Morrey smoothness spaces like <span>(cal{N}_{varphi,p,q}^{s}(mathbb{R}^{d}))</span>, <i>B</i><span>\u0000 <sup><i>s,φ</i></sup><sub><i>p,q</i></sub>\u0000 \u0000 </span>(ℝ<sup><i>d</i></sup>) and <i>F</i><span>\u0000 <sup><i>s,φ</i></sup><sub><i>p,q</i></sub>\u0000 \u0000 </span>(ℝ<sup><i>d</i></sup>). The latter have been investigated in a recent paper by the first two authors (2023), while the embeddings of the scale <span>(cal{N}_{varphi,p,q}^{s}(mathbb{R}^{d}))</span> were mainly obtained in a paper of the first and last two authors (2022). Now we concentrate on the characterisation of the spaces <span>(cal{E}_{varphi,p,q}^{s}(mathbb{R}^{d}))</span>. Our approach requires a wavelet characterisation of those spaces which we establish for the system of Daubechies’ wavelets. Then we prove necessary and sufficient conditions for the embedding <span>(cal{E}_{varphi_{1},p_{1},q_{1}}^{s_{1}}(mathbb{R}^{d})hookrightarrowcal{E}_{varphi_{2},p_{2},q_{2}}^{s_{2}}(mathbb{R}^{d}))</span>. We can also provide some almost final answer to the question when <span>(cal{E}_{varphi,p,q}^{s}(mathbb{R}^{d}))</span> is embedded into <i>C</i>(ℝ<sup><i>d</i></sup>), complementing our recent findings in case of <span>(cal{N}_{varphi,p,q}^{s}(mathbb{R}^{d}))</span>.</p></div>","PeriodicalId":50893,"journal":{"name":"Acta Mathematica Sinica-English Series","volume":"41 1","pages":"413 - 456"},"PeriodicalIF":0.8,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143108859","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":"Weighted Estimates for Generalised Conical Square Functions and Applications","authors":"The Anh Bui, Xuan Thinh Duong, Ji Li","doi":"10.1007/s10114-025-3478-x","DOIUrl":"10.1007/s10114-025-3478-x","url":null,"abstract":"<div><p>Let <span>({cal{A}_{t}}_{t>0})</span> be a family of bounded linear operator on <i>L</i><sup>2</sup>(<i>X</i>) where (<i>X, d, μ</i>) is a metric space with metric <i>d</i> and doubling measure <i>μ</i>. Assume that the family <span>({cal{A}_{t}}_{t>0})</span> satisfies suitable off-diagonal estimates from <span>(L^{p_{0}})</span> to <i>L</i><sup>2</sup> for some <i>p</i><sub>0</sub> < 2. This paper aims to prove weighted bound estimates for conical square functions and g-functions associated to the family <span>({cal{A}_{t}}_{t>0})</span>. Some applications such as weighted bounds for bilinear estimates associated to certain differential operators are also obtained.</p></div>","PeriodicalId":50893,"journal":{"name":"Acta Mathematica Sinica-English Series","volume":"41 1","pages":"191 - 208"},"PeriodicalIF":0.8,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143108862","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}
Nijjwal Karak, Pekka Koskela, Debanjan Nandi, Swadesh Kumar Sahoo
{"title":"Conformal Composition for Borderline Fractional Sobolev Spaces","authors":"Nijjwal Karak, Pekka Koskela, Debanjan Nandi, Swadesh Kumar Sahoo","doi":"10.1007/s10114-025-3649-9","DOIUrl":"10.1007/s10114-025-3649-9","url":null,"abstract":"<div><p>We establish a pointwise property for homogeneous fractional Sobolev spaces in domains with non-empty boundary, extending a similar result of Koskela–Yang–Zhou. We use this to show that a conformal map from the unit disk onto a simply connected planar domain induces a bounded composition operator from the borderline homogeneous fractional Sobolev space of the domain into the corresponding space of the unit disk.</p></div>","PeriodicalId":50893,"journal":{"name":"Acta Mathematica Sinica-English Series","volume":"41 1","pages":"457 - 471"},"PeriodicalIF":0.8,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143108854","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":"Bilinear Exotic Calderón-Zygmund Operators","authors":"Jin Bai, Jinsong Li, Kangwei Li","doi":"10.1007/s10114-025-3589-4","DOIUrl":"10.1007/s10114-025-3589-4","url":null,"abstract":"<div><p>We introduce a bilinear extension of the so-called exotic Calderón-Zygmund operators. These kernels arise naturally from the bilinear singular integrals associated with Zygmund dilations. We show that such a class of operators satisfy a <i>T</i>1 theorem in the same form as the standard Calderón-Zygmund operators. However, one-parameter weighted estimates may fail in general, and unlike the linear case, we are not able to provide the end-point estimates in full generality.</p></div>","PeriodicalId":50893,"journal":{"name":"Acta Mathematica Sinica-English Series","volume":"41 1","pages":"355 - 377"},"PeriodicalIF":0.8,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143108467","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}